26 tools
Paint & Decorating
Paint, wallpaper, stain and decorating time calculators for rooms, ceilings, fences and decks.
Free, no sign up, UK and EU units
Home calculators that show their working
Work out paint, tiles, flooring, energy bills and radiator sizes in seconds. Every answer comes with the formula, a breakdown and rates checked against official sources.
What does it cost to run?
W
hours
Per year£192.14
Per hour52.64p
At the UK price cap of 26.32p per kWh (October to December 2026).
Open the full calculator272free calculators
15home categories
October 2026energy rates checked
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Pick a category
Each category has its own guides and calculators that link together, so one job leads to the next.
19 tools
Flooring & Tiling
Tiles, grout, adhesive, laminate, vinyl, carpet and skirting quantities with wastage built in.
49 tools
Energy & Bills
Electricity, gas, solar, EV charging and tariff calculators using current UK and EU prices.
15 tools
Solar & Batteries
Solar panel cost, output, roof space, export, batteries, off grid systems, charge controllers and finance.
27 tools
Heating & Insulation
Radiator, boiler, heat pump, underfloor heating and loft insulation sizing tools.
20 tools
Kitchen & Cooking
Cups, spoons, oven temperatures, cooking times and recipe scaling for UK, EU and US recipes.
7 tools
Bed & Home Sizes
Bed, duvet, pillow, sheet, towel, photo frame and light bulb size converters for UK, EU and US.
14 tools
Room & Space
Room area, volume, rugs, curtains, blinds, TV distance, tables, worktops and moving boxes.
31 tools
Building & DIY
Concrete, bricks, blocks, mortar, gravel, sand, decking, fencing, plaster and paving quantities.
16 tools
Garden & Outdoor
Topsoil, mulch, compost, turf, artificial grass, grass seed, lawn feed, raised beds, sleepers and pond liners.
7 tools
Energy & Heat Units
kWh, BTU, therms, watts, amps, gas meter units and heating oil converted with the exact factors.
11 tools
Area & Volume
Square feet, square metres, cubic metres, litres, gallons, feet and inches, cm and tonnes of aggregate.
12 tools
Water & Plumbing
Water bills, usage, flow rates, tank and cylinder sizes, softeners, rainwater harvesting and dripping taps.
10 tools
Lighting & Electrical
Lumens, LED savings, plug fuses, extension leads, generators, inverters, battery backup and appliance wattage.
8 tools
Cleaning & Laundry
Bleach and cleaning dilutions, detergent doses, laundry loads, wash care symbols, stain removal and cleaner costs.
Most used calculators
Start with the tools people reach for first when planning a room, a bill or a heating upgrade.
Paint CalculatorLitres and tins of paint for any room, with doors, windows and coats.PaintTile CalculatorTiles and boxes for floors and walls, with grout gaps and wastage.FlooringElectricity Cost CalculatorRunning cost of any appliance per hour, day, month and year.EnergyRadiator Size CalculatorHeat output in watts and BTU a room needs, using a simple heat loss method.HeatingGas Bill CalculatorConvert gas meter readings to kWh and work out the bill.EnergyLaminate Flooring CalculatorPacks of laminate, underlay rolls and cost for any room.FlooringWallpaper CalculatorRolls of wallpaper for a room, allowing for pattern repeat and trimming.PaintSolar Panel CalculatorYearly output, savings and payback for a home solar PV system.EnergyHeat Pump Running Cost CalculatorYearly heat pump running cost compared with a gas boiler.EnergyCarpet CalculatorCarpet, underlay and gripper rod for a room from 4 m or 5 m rolls.FlooringRadiator Output CalculatorReal radiator output at your flow temperature using the Delta T correction.HeatingElectricity Bill CalculatorYour bill from meter readings, unit rate and daily standing charge.Energy
All calculators by category
Every HousyTools calculator, grouped by the job you are doing. Pick a category to jump straight to its tools.
Paint & Decorating
Paint, wallpaper, stain and decorating time calculators for rooms, ceilings, fences and decks.
Paint CalculatorLitres and tins of paint for any room, with doors, windows and coats.Ceiling Paint CalculatorHow much ceiling paint you need for one room or the whole floor.Wallpaper CalculatorRolls of wallpaper for a room, allowing for pattern repeat and trimming.Paint Cost CalculatorWhat the paint for a job will cost, including primer and sundries.Masonry Paint CalculatorExterior masonry paint for render, brick and pebbledash walls.Fence Paint CalculatorFence paint or treatment for panels, by panel size, sides and coats.Deck Stain CalculatorDecking stain or oil needed for your deck size and number of coats.Painting Time CalculatorHow long painting a room takes, including prep and drying between coats.Primer CalculatorWorks out how much primer you need in litres and tins for walls, ceilings and woodwork.Floor Paint CalculatorWorks out how much floor paint you need in litres and tins for garages and rooms.Wood Varnish CalculatorWorks out the litres and tins of wood varnish needed for floors, doors and furniture.Mist Coat CalculatorWorks out the paint and water you need to mist coat new plaster in a room.Door Paint CalculatorWorks out how much paint and how many tins you need to paint your doors.Spray Paint Coverage CalculatorWorks out how many aerosol cans of spray paint you need for a surface and coats.Lining Paper CalculatorWorks out how many rolls of lining paper you need for a room's walls and ceiling.Paint Drying Time CalculatorWorks out paint touch dry and recoat times for your temperature, plus when the job finishes.Exterior Paint CalculatorWorks out how much exterior masonry paint you need for house walls, gables and coats.Gloss Paint CalculatorWorks out gloss and undercoat for doors, frames, skirting boards and window frames.Wallpaper Paste CalculatorWorks out the packets or tubs of wallpaper paste needed for your rolls or room.Wallpaper Pattern Repeat CalculatorWorks out drop length, drops per roll and rolls needed for patterned wallpaper with a repeat.Painter Labour Cost CalculatorEstimates hours, days and labour cost of a painting job from areas and a day rate.Skirting Board Paint CalculatorWorks out how much paint and how many tins you need for a room's skirting boards.Staircase Paint CalculatorWorks out the paint for stair treads, risers, stringers, spindles, handrail and newel posts.Window Frame Paint CalculatorWorks out the paint and tins needed for timber window frames, sashes and sills.Feature Wall Paint CalculatorWorks out paint for a feature wall and, separately, for the other walls in the room.Tile Paint CalculatorWorks out how much tile paint and primer you need for wall tiles or a splashback.
Flooring & Tiling
Tiles, grout, adhesive, laminate, vinyl, carpet and skirting quantities with wastage built in.
Tile CalculatorTiles and boxes for floors and walls, with grout gaps and wastage.Laminate Flooring CalculatorPacks of laminate, underlay rolls and cost for any room.Vinyl Flooring CalculatorLength of sheet vinyl to buy from 2, 3 or 4 m wide rolls.Carpet CalculatorCarpet, underlay and gripper rod for a room from 4 m or 5 m rolls.Grout CalculatorKilograms and bags of grout from tile size, joint width and depth.Tile Adhesive CalculatorBags of tile adhesive by area and notched trowel size.Skirting Board CalculatorMetres and lengths of skirting board for a room, less door openings.Self Levelling Compound CalculatorBags of floor levelling compound by area and average depth.Herringbone Tile CalculatorWorks out how many herringbone tiles and boxes you need, with extra for cuts.Stair Carpet CalculatorWorks out stair carpet area, the roll length to buy, underlay and cost for any staircase.Tile Backer Board CalculatorWorks out how many tile backer boards, fixings and metres of joint tape you need.Silicone Sealant CalculatorWorks out how many cartridges of silicone sealant you need and how far one goes.Epoxy Floor CalculatorWorks out how much epoxy floor coating you need in litres, kilograms and kits.Bathroom Tile CalculatorWorks out the wall and floor tiles and boxes needed to tile a bathroom.Flooring Cost CalculatorWorks out the total cost of new flooring, with packs, underlay, fitting and extras.Engineered Wood Flooring CalculatorWorks out packs of engineered wood flooring, underlay or adhesive, beading and cost for a room.Kitchen Splashback Tile CalculatorWorks out tiles, rows, columns and boxes for a kitchen splashback, including brick bond.Carpet Underlay CalculatorWorks out underlay rolls, strips, seam tape, gripper rod and door bars for a carpeted room.Parquet Flooring CalculatorWorks out parquet blocks, packs, adhesive and edge beading for a room, with wastage.
Energy & Bills
Electricity, gas, solar, EV charging and tariff calculators using current UK and EU prices.
Electricity Cost CalculatorRunning cost of any appliance per hour, day, month and year.Electricity Bill CalculatorYour bill from meter readings, unit rate and daily standing charge.Gas Bill CalculatorConvert gas meter readings to kWh and work out the bill.Solar Panel CalculatorYearly output, savings and payback for a home solar PV system.Heat Pump Running Cost CalculatorYearly heat pump running cost compared with a gas boiler.EV Charging Cost CalculatorCost of charging an electric car at home, per charge, per mile and per year.Economy 7 CalculatorCheck if Economy 7 beats a single rate tariff for your usage.Electric Shower Cost CalculatorCost per shower and per year for 8.5 to 10.8 kW electric showers.Tumble Dryer Running Cost CalculatorWorks out what each tumble dryer cycle costs, plus weekly, monthly and yearly totals.Washing Machine Running Cost CalculatorWorks out what each wash costs in electricity, plus weekly and yearly totals.Dishwasher Running Cost CalculatorWorks out what each dishwasher cycle costs in electricity, plus weekly and yearly totals.Fridge Freezer Running Cost CalculatorWorks out what a fridge freezer costs per day, month and year, and compares models.Air Fryer Running Cost CalculatorWorks out what an air fryer costs per use, week and year, compared with an oven.Kettle Running Cost CalculatorWorks out what each kettle boil costs, plus daily and yearly totals, from water or wattage.Electric Heater Running Cost CalculatorWorks out what an electric heater costs to run per hour, day, week and year.Dehumidifier Running Cost CalculatorWorks out what a dehumidifier costs to run per hour, day, week and year.Immersion Heater Cost CalculatorWorks out the cost and time to heat a hot water cylinder with an immersion heater.Hot Tub Running Cost CalculatorWorks out a hot tub's heating and running cost per day, week, month and year.Standby Power Cost CalculatorWorks out what devices left on standby cost you per day, month and year.Solar Battery Size CalculatorWorks out the battery size your solar panels can fill, plus yearly savings and payback.Balcony Solar Power CalculatorEstimates a plug-in balcony solar kit's yearly output, bill savings and payback time.Heat Pump vs Gas Boiler Cost CalculatorCompares yearly heating costs of a gas boiler and a heat pump, with break-even efficiency.Solar Panel Payback CalculatorWorks out how many years solar panels take to pay back and the 25 year savings.Energy Price Cap CalculatorWorks out your yearly and monthly energy bill under the current Ofgem price cap.Air Conditioner Running Cost CalculatorWorks out what an air conditioner costs to run per hour, day and summer.Oil Filled Radiator Running Cost CalculatorWorks out what an oil filled radiator costs per hour, day and winter, compared with gas.Time of Use Tariff CalculatorCompares a time of use electricity tariff with a standard single rate tariff for your usage.Standing Charge CalculatorWorks out what electricity and gas standing charges cost you and their share of the bill.Gaming PC Electricity Cost CalculatorWorks out what your gaming PC and monitor cost to run per hour, day and year.Oven Running Cost CalculatorWorks out what an electric oven costs per use, per week and per year.TV Running Cost CalculatorWorks out what your TV costs per hour, per day and per year, including standby.Electric Blanket Running Cost CalculatorWorks out what an electric blanket costs per night and per winter, compared with a heater.Microwave Running Cost CalculatorWorks out what a microwave costs per minute, per use and per year, including standby.Slow Cooker Running Cost CalculatorWorks out what a slow cooker costs per meal, per portion and per year.Home Carbon Footprint CalculatorWorks out your home's yearly carbon footprint from electricity, gas, oil and LPG use.Electric Towel Rail Running Cost Calculator NewWorks out what an electric towel rail costs per hour, day and year to run.Storage Heater Running Cost Calculator NewWorks out the cost of charging storage heaters overnight on Economy 7, plus any daytime boost.Underfloor Heating Running Cost Calculator NewWorks out the running cost of electric underfloor heating from area, output and hours.Heated Airer Running Cost Calculator NewWorks out what a heated clothes airer costs per load and per year, and compares it with a tumble dryer.Induction Hob Running Cost Calculator NewWorks out what an induction hob costs to cook with and compares it with a gas hob.Fan Running Cost Calculator NewWorks out what an electric fan costs to run per hour, per night and per summer.Hair Dryer Running Cost Calculator NewWorks out what a hair dryer costs per use, per week and per year.Coffee Machine Running Cost Calculator NewWorks out the electricity cost per cup and per year of a coffee machine, including warm up and standby.Sauna Running Cost Calculator NewWorks out what a home sauna costs per session and per year, including heat up time.Iron Running Cost Calculator NewWorks out what an iron or steam generator costs per session and per year.Aquarium Running Cost Calculator NewWorks out what a fish tank heater, filter and light cost to run per month and per year.Electric Fireplace Running Cost Calculator NewWorks out what an electric fire costs to run on flame effect only or with the heater on.Chest Freezer Running Cost Calculator NewWorks out what a chest freezer costs per year from its energy label, and the saving from replacing an old one.Wine Cooler Running Cost Calculator NewWorks out what a wine cooler or wine fridge costs per year, per month and per bottle space.
Solar & Batteries
Solar panel cost, output, roof space, export, batteries, off grid systems, charge controllers and finance.
Solar Panel Cost CalculatorEstimates the installed price of home solar panels, with battery, scaffolding and VAT.How Many Solar Panels CalculatorWorks out how many solar panels and how much roof you need to cover your electricity use.Solar Panel Output CalculatorShows how many kWh your solar panels make per day, month and year, summer and winter.Solar Battery Savings CalculatorShows what a battery adds to your solar savings and how long it takes to pay back.Solar Export CalculatorWorks out what you earn from exporting solar power and compares two export tariffs.Solar Panel Angle CalculatorFinds the solar panel tilt that faces the midday sun in each season, and checks your roof pitch.Solar Roof Space CalculatorWorks out how many solar panels fit on a roof, in portrait or landscape, and the system size.Off Grid Solar CalculatorSizes the solar panels and battery bank for an off grid cabin, van or outbuilding.Solar Charge Controller CalculatorWorks out the charge controller amps and voltage you need for your panels and battery.Solar Panel Finance CalculatorCompares monthly loan repayments for solar panels with the savings they make.Solar EV Charging CalculatorWorks out how many solar panels charge an electric car and what solar charging saves.Solar Diverter CalculatorShows what a solar immersion diverter saves on hot water and how fast it pays back.Solar String CalculatorChecks string voltage and current against your inverter limits, with cold weather correction.Solar Panel Degradation CalculatorShows how solar panel output falls each year and the total energy over the panel life.Solar Battery Charge Time CalculatorWorks out how long a solar panel takes to charge a 12 V, 24 V or 48 V battery.
Heating & Insulation
Radiator, boiler, heat pump, underfloor heating and loft insulation sizing tools.
Radiator Size CalculatorHeat output in watts and BTU a room needs, using a simple heat loss method.Radiator Output CalculatorReal radiator output at your flow temperature using the Delta T correction.Boiler Size CalculatorA guide kW range for combi, system or regular boilers.Heat Pump Size CalculatorEstimate the heat pump kW from floor area or your yearly gas use.Underfloor Heating CalculatorElectric mat wattage and running cost, or wet system pipe length.Loft Insulation CalculatorRolls of loft insulation to reach the recommended 270 mm depth.BTU CalculatorWorks out the heat a room needs in BTU per hour and watts from its size and insulation.Room Heat Loss CalculatorCalculates a room's heat loss in watts through each wall, window, ceiling, floor and air.Heating Oil Cost CalculatorWorks out what heating oil costs per order, per year and per kWh of heat.Heating Oil Tank CalculatorWorks out oil tank capacity, litres left from a dip reading, top up and days remaining.U-Value CalculatorWorks out the U-value of a wall, roof or floor from its layers, plus heat loss.Wood Burner Size CalculatorWorks out the stove size in kW and BTU for a room, plus air vent needs.Dehumidifier Size CalculatorWorks out the dehumidifier capacity in litres per day for your floor area and dampness.Air Conditioner BTU CalculatorWorks out the air conditioner cooling capacity in BTU/h and kW for a room.Dew Point CalculatorWorks out the dew point from temperature and humidity, and checks a surface for condensation.Underfloor Heating Mat CalculatorWorks out the electric underfloor heating mat size, wattage, current and running cost for a room.Heating Cost Per Room CalculatorEstimates the daily and yearly cost of heating one room by gas, electric or heat pump.Cavity Wall Insulation Savings CalculatorEstimates the heat, fuel and money that filling your cavity walls could save each year.Insulation Board CalculatorWorks out how many insulation boards you need and the thickness to reach a target U-value.R-Value to U-Value CalculatorConverts R-values to U-values and back, in metric and US units, with optional surface resistances.Hot Water Cylinder Size CalculatorEstimates the hot water cylinder size your household needs, plus heat-up energy and time.Firewood CalculatorWorks out how many kilograms and cubic metres of logs your stove burns in a season.Double Glazing Savings CalculatorEstimates the heat, fuel and money new double or triple glazing could save each year.Delta T Correction CalculatorCorrects a radiator's Delta T 50 output to your real flow, return and room temperatures.Pellet Consumption CalculatorWorks out how many kilograms and bags of wood pellets a stove or boiler burns.Pipe Insulation CalculatorWorks out the pipe lagging lengths to buy and the heat and money insulation saves.Expansion Vessel Size CalculatorSizes a sealed heating system expansion vessel from water volume, temperatures and pressures.
Kitchen & Cooking
Cups, spoons, oven temperatures, cooking times and recipe scaling for UK, EU and US recipes.
Cups to Grams ConverterConverts cups to grams, or grams to cups, for 28 common baking ingredients.Oven Temperature ConverterConverts oven temperatures between Celsius, fan oven Celsius, Fahrenheit and gas mark.Gas Mark ConverterConverts gas marks to Celsius, Fahrenheit and fan oven settings, and back again.Fan Oven Temperature ConverterConverts conventional oven temperatures to fan oven settings, and fan settings back again.Tablespoons to Grams ConverterConverts tablespoons to grams, or grams to tablespoons, for 28 common cooking ingredients.Teaspoons to Grams ConverterConverts teaspoons to grams, or grams to teaspoons, for 22 common kitchen ingredients.Ml to Grams ConverterConverts millilitres to grams, or grams to millilitres, using the density of 22 kitchen ingredients.Butter Sticks to Grams ConverterConverts US sticks of butter to grams, or grams to sticks, with tablespoons and cups.Ounces to Grams ConverterConverts ounces to grams, or grams to ounces, with pounds and troy ounces too.Fluid Ounces to Ml ConverterConverts UK or US fluid ounces to millilitres, or millilitres back to fluid ounces.Pints to Ml ConverterConverts UK or US pints to millilitres and back, with litres and fluid ounces.Cake Tin Size ConverterScales a cake recipe from one tin size or shape to another by base area.Air Fryer Conversion CalculatorConverts oven temperatures and cooking times to air fryer settings, or back again.Microwave Wattage ConverterAdjusts microwave cooking times from the wattage on the pack to your microwave.Egg Size ConverterWorks out how many eggs of your size replace the eggs a recipe asks for.Recipe ScalerScales recipe ingredient amounts up or down for any number of servings.Rice to Water Ratio CalculatorWorks out how much water to add for your amount and type of rice.Fresh to Dry Yeast ConverterConverts fresh yeast to fast action or dried active yeast, and back again.Turkey Cooking Time CalculatorWorks out turkey roasting time by weight using UK Food Standards Agency guidance.Meat Roasting Time CalculatorWorks out roasting time and oven timings for beef, lamb, pork and chicken by weight.
Bed & Home Sizes
Bed, duvet, pillow, sheet, towel, photo frame and light bulb size converters for UK, EU and US.
Bed Size ConverterFinds the closest UK, EU, US or Australian bed size to any mattress you have.Duvet Size ConverterMatches UK, EU and US duvet sizes and shows the overhang on your mattress.Pillow Size ConverterFinds the closest UK, European or US pillow size to the pillow you have.Bed Sheet Size ConverterWorks out the fitted and flat sheets your mattress needs in UK, EU or US sizes.Towel Size ConverterConverts towel names to sizes in cm and inches, or names a towel from its size.Photo Frame Size ConverterConverts photo frame sizes between inches, centimetres and A sizes, and finds the frame to buy.Light Bulb Base ConverterIdentifies light bulb bases from a code or measurement and gives UK, EU and US equivalents.
Room & Space
Room area, volume, rugs, curtains, blinds, TV distance, tables, worktops and moving boxes.
Square Metre CalculatorWorks out square metres for rectangles, circles and triangles, with extra and cost.Room Volume CalculatorWorks out a room's volume in cubic metres, cubic feet and litres, plus airflow needed.Irregular Room Area CalculatorWorks out the floor area of L-shaped and irregular rooms by adding sections and subtracting cut-outs.Rug Size CalculatorWorks out the right rug size for a living room, dining room or bedroom.Curtain Size CalculatorWorks out pole length, curtain drop, curtain width and the nearest UK ready made size.Curtain Fabric CalculatorWorks out how many metres of curtain fabric and lining to buy, including pattern repeat.Blind Size CalculatorWorks out the blind width and drop to order for inside or outside recess fitting.TV Size and Viewing Distance CalculatorWorks out the best TV size for your seat, or the best seat for your TV.Dining Table Size CalculatorWorks out the table size your diners need and the largest table your room fits.Kitchen Worktop CalculatorWorks out worktop area, how many standard lengths to buy, joints and upstand length.Moving Box CalculatorEstimates how many small, medium and large moving boxes and tape rolls you need.Picture Hanging Height CalculatorWorks out where to put the nail or hooks so a picture hangs at eye level.Sofa Size CalculatorWorks out the longest sofa a wall suits, seats, walkway space and doorway fit.Ceiling Fan Size CalculatorWorks out the ceiling fan blade diameter for your room and checks the blade height.
Building & DIY
Concrete, bricks, blocks, mortar, gravel, sand, decking, fencing, plaster and paving quantities.
Concrete CalculatorWorks out concrete volume in cubic metres, weight in tonnes and bags of ready mix.Concrete Post Hole CalculatorWorks out concrete per post hole, total volume, weight and bags for fence posts.Brick CalculatorWorks out how many bricks you need for a wall, with bricks per m² and mortar.Block CalculatorWorks out how many concrete blocks you need for a wall, plus weight and mortar.Mortar CalculatorWorks out mortar volume, cement bags, sand and premix bags for brick or block walls.Gravel CalculatorWorks out how much gravel you need in cubic metres, tonnes and bags for an area.Sand CalculatorWorks out how much sand you need in cubic metres, tonnes, bags and bulk bags.Decking CalculatorWorks out decking boards, joists, screws and screw length for a rectangular deck.Fence Panel CalculatorWorks out fence panels, posts, gravel boards, post length and post mix for a fence run.Plaster CalculatorWorks out how many bags of finishing or undercoat plaster you need for walls and ceilings.Plasterboard CalculatorWorks out plasterboard sheets, screws and screw length for walls and ceilings.Patio Slab CalculatorWorks out paving slabs, Type 1 sub base, sharp sand and cement for a patio.Block Paving CalculatorWorks out paving blocks, Type 1 sub base, laying course sand and jointing sand needed.Render CalculatorWorks out bags of render, or sand and cement, to render an outside wall.Roof Pitch CalculatorWorks out roof pitch in degrees, ratio and percent, plus rafter length and roof area.Stair CalculatorWorks out stair risers, rise, going, pitch and total run, checked against Approved Document K.Skip Size CalculatorWorks out your waste volume in cubic metres and yards and the skip size to hire.Cement CalculatorWorks out the bags of cement, sand and gravel a concrete or mortar job needs.Roof Tile CalculatorWorks out roof tiles, battens, ridge tiles and roof weight from your roof size.Ballast CalculatorWorks out the tonnes and bulk bags of ballast, plus cement, for a concrete job.Hardcore CalculatorWorks out hardcore or Type 1 sub-base needed in cubic metres, tonnes and bulk bags.Sand and Cement Screed CalculatorWorks out screed volume, cement bags and tonnes of sharp sand for a floor.Stud Wall CalculatorWorks out studs, plates, noggins, timber lengths, plasterboard sheets and screws for a stud wall.Paving CalculatorWorks out how many paving slabs or blocks you need, plus sub-base and bedding tonnes.Guttering CalculatorWorks out gutter lengths, brackets, downpipes and fittings, and checks rainwater flow per outlet.Joist Span CalculatorChecks a C24 floor joist size against your span and finds the smallest size that works.Retaining Wall Block CalculatorWorks out blocks, courses, coping, footing concrete and drainage gravel for a garden retaining wall.Concrete Footing CalculatorWorks out the concrete volume, tonnes and bags for pad, strip or round footings.Timber CalculatorWorks out timber volume in cubic metres, linear metres, weight and stock lengths to buy.Roofing Felt CalculatorWorks out rolls of shed felt, overlaps and clout nails for a pent or apex roof.Rubble Volume CalculatorWorks out rubble volume, bulked loose volume, weight in tonnes, bulk bags and skip size.
Garden & Outdoor
Topsoil, mulch, compost, turf, artificial grass, grass seed, lawn feed, raised beds, sleepers and pond liners.
Topsoil Calculator NewWorks out how much topsoil you need in cubic metres, tonnes, bags and bulk bags.Mulch Calculator NewWorks out how much bark or mulch you need for a border, in litres, cubic metres and bags.Compost Calculator NewWorks out how much compost you need to dig in or spread over beds and borders.Turf Calculator NewWorks out how many rolls of turf you need for a lawn, with extra for cutting and the cost.Artificial Grass Calculator NewWorks out the artificial grass to buy from 2 m or 4 m rolls, joins, tape and cost.Grass Seed Calculator NewWorks out how much grass seed you need for a new lawn or for overseeding.Lawn Fertiliser Calculator NewWorks out how much lawn feed to spread per application and per year, and how many bags.Raised Bed Soil Calculator NewWorks out the soil and compost needed to fill raised beds, in litres and bags.Garden Sleeper Calculator NewWorks out how many sleepers you need for a raised bed or edging, layer by layer.Pond Liner Calculator NewWorks out the pond liner and underlay size you need from the pond length, width and depth.Pond Volume Calculator NewWorks out how many litres and gallons a pond holds, and the pump flow needed to turn the water over.Hedge Planting Calculator NewWorks out how many hedge plants you need from the hedge length, spacing and number of rows.Greenhouse Heater Running Cost Calculator NewWorks out what an electric greenhouse heater costs per night and per winter with a thermostat.Garden Lighting Running Cost Calculator NewWorks out what mains garden lights cost to run per night and per year, and the saving from LED bulbs.Hose Water Use Calculator NewWorks out how many litres a garden hose uses per session and per year, and the cost on a water meter.Patio Heater Running Cost Calculator NewWorks out what an electric or gas patio heater costs per evening and per year.
Energy & Heat Units
kWh, BTU, therms, watts, amps, gas meter units and heating oil converted with the exact factors.
kWh to BTU ConverterConverts kWh to BTU and back, plus kW to BTU per hour for air conditioners.Watts to Amps ConverterConverts watts to amps, or amps to watts, for single phase, three phase and DC circuits.Gas m3 to kWh ConverterConverts gas meter units in cubic metres or cubic feet to kWh, and back.Therms to kWh ConverterConverts UK, EU or US therms to kilowatt hours, or kilowatt hours back to therms.Heating Oil Litres to kWh ConverterConverts heating oil litres to kWh or back, with useful heat and cost per kWh.BTU to Watts ConverterConverts BTU per hour to watts and kilowatts, or watts back to BTU per hour.Watts to kWh ConverterConverts watts and hours of use to kWh and cost, or kWh back to average watts.
Area & Volume
Square feet, square metres, cubic metres, litres, gallons, feet and inches, cm and tonnes of aggregate.
Square Feet to Square Metres ConverterConverts square feet to square metres, or square metres to square feet, with yards and acres.Cubic Metre CalculatorWorks out volume in cubic metres for boxes, rooms and cylinders, plus litres and cubic feet.Litres to Gallons ConverterConverts litres to UK or US gallons and back, with pints and cubic metres shown.Feet and Inches to Metres ConverterConverts feet and inches to metres and centimetres, or metres back to feet and inches.Cm to Inches ConverterConverts centimetres to inches and back, with fractions to the nearest sixteenth and feet.Tonnes to Cubic Metres Aggregate ConverterConverts tonnes of sand, gravel, sub-base or topsoil to cubic metres and back, with coverage.Mm to Inches ConverterConverts millimetres to inches, as decimals and tape measure fractions, or inches back to mm.Cubic Metres to Litres ConverterConverts cubic metres to litres and back, or works out litres from tank dimensions.Square Yards to Square Metres ConverterConverts square yards to square metres or back, and converts prices per square yard.Cubic Feet to Cubic Metres ConverterConverts cubic feet to cubic metres or back, or measures a space in feet, with litres.Cubic Yards to Cubic Metres ConverterConverts cubic yards to cubic metres or back, with the tonnes of concrete, sand or soil.
Water & Plumbing
Water bills, usage, flow rates, tank and cylinder sizes, softeners, rainwater harvesting and dripping taps.
Water Bill CalculatorEstimates a metered water and sewerage bill per year and per month from your water use.Dripping Tap Cost CalculatorWorks out how much water a dripping tap wastes and its cost per day and year.Combi Boiler Flow Rate CalculatorWorks out a combi boiler's hot water flow rate and checks your mains flow and showers.Water Usage CalculatorAdds up your household's daily water use by activity, with litres per person and yearly cost.Shower Water Usage CalculatorWorks out litres per shower and the water and heating cost for any shower type.Water Tank Size CalculatorWorks out a tank's litres and gallons at any depth, plus water weight and supply days.Water Softener Size CalculatorWorks out the daily hardness load and the softener capacity your household needs.Rainwater Harvesting CalculatorWorks out how much rainwater your roof can collect, the tank size and the yearly saving.Pipe Flow Rate CalculatorWorks out pipe flow rate from velocity or a bucket test, and water speed from flow.Hot Water Usage CalculatorWorks out daily hot water litres, the energy to heat it and the yearly cost.Pipe Volume CalculatorWorks out how many litres a pipe holds and how long hot water takes to arrive.Water Meter Savings CalculatorCompares your unmetered water bill with an estimated metered bill to show any saving.
Lighting & Electrical
Lumens, LED savings, plug fuses, extension leads, generators, inverters, battery backup and appliance wattage.
Lumens CalculatorWorks out how many lumens and light bulbs a room needs for a target brightness.Plug Fuse CalculatorFinds the right UK plug fuse, 3 A or 13 A, from the appliance watts.Generator Size CalculatorWorks out the generator size in kW and kVA for the appliances you want to run.Lumens to Watts CalculatorConverts lumens to watts for LED, CFL, halogen and old bulbs, and sizes room lighting.LED Savings CalculatorWorks out how much switching old bulbs to LEDs saves each year, and the payback time.Inverter Size CalculatorWorks out the inverter watts, surge rating and battery current your appliances need.Battery Backup Runtime CalculatorWorks out how long a battery runs your appliances, or the battery size you need.Downlight Spacing CalculatorWorks out how many downlights a room needs, the grid layout and the spacing.Extension Lead Load CalculatorAdds up appliance watts to check an extension lead stays within its amp rating.Christmas Lights Cost CalculatorWorks out Christmas lights running costs per day and per season, LED or old style.
Cleaning & Laundry
Bleach and cleaning dilutions, detergent doses, laundry loads, wash care symbols, stain removal and cleaner costs.
Bleach Dilution CalculatorWorks out how much bleach and water to mix for a chosen chlorine strength in ppm.Laundry Detergent Dose CalculatorScales the pack detergent dose to your load, with washes and cost per wash.Washing Machine Capacity CalculatorWeighs up your laundry load against the drum capacity and suggests the right machine size.Laundry Symbols DecoderTurns the care symbols on a clothing label into plain washing, drying and ironing instructions.Dilution Ratio CalculatorWorks out how much concentrate and water to mix for any dilution ratio.Stain Remover FinderFinds the right first treatment, water temperature and method for common household stains.Vinegar Cleaning Ratio CalculatorWorks out how much vinegar and water to mix for a cleaning job and bottle size.Cleaner Cost CalculatorWorks out what a house cleaner costs per visit, month and year from your rate.
Latest home guides
Step by step answers on paint, flooring, energy bills and boiler or washing machine error codes, checked against official sources.
Energy and Bills Guides
Bath or Shower: Which Is Cheaper?
Compare the real cost of a bath and a shower at October 2026 rates, including electric, mixer and power showers and break-even times.
7 min read
Energy and Bills Guides
How Gas Meter Readings Convert to kWh
See how a gas meter reading converts to kWh using the calorific value, the 1.02264 correction factor and current price cap rates.
6 min read
Washing Machine Guides
Why Washing Machines Throw Drain Errors
Find out why washing machines throw drain errors, what each brand code means, and the safe checks that clear most blockages.
8 min read
Washing Machine Guides
How to Reset a Washing Machine
Learn how to reset a washing machine safely with a power cycle, brand button sequences and the checks to make before you reset.
8 min read
Washing Machine Guides
How to Clean a Washing Machine Filter
Learn how to clean a washing machine filter safely, how often manufacturers recommend it, and what to do if the filter is stuck.
9 min read
Boiler Guides
Combi vs System vs Heat Pump
Compare combi boilers, system boilers and heat pumps on hot water, space, installation cost, grants and running costs to find the right fit for…
7 min read
How we keep the numbers right
We would rather show you the working than ask you to trust a black box.
Primary sources
Rates and rules come from regulators, standards and manufacturer data sheets, such as Ofgem, Eurostat and paint and adhesive technical sheets.
Formula on every result
Open "Show the formula and working" under any answer to see each step, so you can check it or use it on paper.
Checked and dated
Each page carries a "Checked" date. Energy prices are reviewed whenever a new price cap period starts.
Free home improvement calculators for UK and EU homes
HousyTools is a set of free home improvement calculators for people who are about to paint a room, lay a floor, check an energy bill or size a radiator. Each tool works in metric by default, switches to feet and inches where people still use them, and shows prices in pounds or euros.
The aim is simple: give you a number you can act on today, and show exactly how it was worked out. Open “Show the formula and working” under any result and you will see every step, from the wall area to the litres of paint, or from the meter reading to the final bill.
What can these home improvement calculators work out?
Our home improvement calculators cover four everyday jobs: decorating, flooring, energy bills and heating. Pick the job and the calculator asks only for the measurements that matter, then rounds up to the tins, packs, bags or rolls you can actually buy.
Paint and decorating
Work out litres of paint for walls and ceilings, rolls of wallpaper with pattern repeat, masonry paint for render and pebbledash, fence and deck treatments, the cost of the paint and how long the job will take. Start with the paint calculator or browse all paint and decorating calculators.
Flooring and tiling
Count tiles and boxes, grout and adhesive, laminate packs and underlay, sheet vinyl and carpet from standard roll widths, skirting board lengths and levelling compound. Every flooring tool adds wastage for the layout you choose. The tile calculator is the most used, and the flooring calculators page lists the rest.
Energy and bills
Find the running cost of any appliance, check an electricity or gas bill from meter readings, estimate solar panel savings, compare a heat pump with a gas boiler, price an EV charge and see whether Economy 7 suits you. The energy bill calculators use the current UK price cap or EU averages, or your own tariff.
Heating and insulation
Size a radiator in watts and BTU, see the real output of a radiator at lower flow temperatures, get a guide size for a boiler or heat pump, plan underfloor heating and count rolls of loft insulation. Start with the radiator size calculator or open all heating calculators.
Which home improvement calculator should you start with?
Start with the calculator that matches the first thing you need to buy or decide. The table shows the question each of our most used home improvement calculators answers, with the result it gives for its example inputs, so you can see the kind of answer to expect before you type your own numbers.
| Calculator | Question it answers | Example result |
|---|---|---|
| Paint Calculator | How many litres for a 4 m by 3.5 m room? | 5.5 litres |
| Tile Calculator | How many 600 by 300 mm tiles for 7.5 m²? | 46 tiles |
| Laminate Flooring Calculator | How many packs for a 4 m by 3.5 m room? | 8 packs |
| Electricity Cost Calculator | What does 2,000 W for 2 hours a day cost a year? | £384.25 |
| Gas Bill Calculator | What do 100 m³ of gas cost over 30 days? | £98.33 |
| Radiator Size Calculator | How much heat does a 4 m by 3.5 m living room need? | 558 W |
| Radiator Output Calculator | What does a 1,500 W radiator give at 55/45°C? | 739 W |
| Heat Pump Size Calculator | What size heat pump for a 90 m² home? | 4.5 kW |
If your job is not in the table, open the search with Ctrl K, type a word such as “grout”, “solar” or “loft”, and jump straight to the right tool. New home improvement calculators are added to the same four categories over time, and each one appears in the menu as soon as it goes live.
Prefer to compare before you choose? Each category page explains which tool to use first, which numbers to gather, and the common mistakes that make estimates go wrong, such as forgetting the grout joint in a tile count or using an old tariff in a bill check.
Why are these numbers worth trusting?
Every default value is either taken from an official or manufacturer source or clearly marked as an example you should replace. Energy prices come from the regulator, such as the Ofgem price cap, and EU averages from Eurostat. Coverage rates for paint, grout and adhesive follow the published technical data sheets.
Each page shows a “Checked” date. When a regulator changes a rate, we update the calculator and the date together. You can read the full method on how our calculators work and our editorial policy.
Our home improvement calculators never hide the sum. Under every answer you can open the working, so you can check it against a quote, repeat it on paper or show it to a tradesperson.
How do you get the most accurate result?
Accurate inputs matter more than anything else when you use home improvement calculators, so a few minutes with a tape measure and your latest bill pay off. Follow these steps with any of our home improvement calculators:
- Measure in metres to two decimal places, or switch to imperial before you type.
- Measure each wall or floor area separately in an L shaped room, then add them together.
- Use the coverage or pack size printed on the product you will actually buy.
- Enter your own tariff from your latest bill rather than an average.
- Add a little extra for wastage on awkward rooms, and buy materials from the same batch.
- For gas, electrics and structural work, use the result to plan, then ask a qualified professional.
How do you plan a whole room with several calculators?
Most jobs need two or three home improvement calculators in a row, and the results feed each other. A typical bedroom makeover might start with the paint calculator for the walls, move to the ceiling paint and skirting board tools, then finish with the laminate flooring calculator and underlay.
For a heating upgrade, size each room with the radiator size tool first, then use the radiator output calculator to see whether your existing radiators are big enough at a lower flow temperature. After that, a heat pump size estimate and the running cost comparison show whether the switch makes sense for your home.
Because every result can be copied as a link that keeps your numbers, you can save each step and come back to it later, or send the whole plan to a partner or installer.
Are these calculators suitable for homes outside the UK?
Yes, our home improvement calculators are built for the UK first and the rest of Europe second, and they work anywhere metric units are used. Paint and flooring quantities depend only on measurements and product data, so they apply in any country.
Energy tools include UK price cap rates and EU averages from Eurostat, with presets for Germany and Ireland. If you live elsewhere, choose “My own tariff” and type the unit rate and standing charge from your bill. Currency switches between pounds and euros, and pence or cents follow automatically.
Home improvement calculators FAQs
Are HousyTools calculators free?
Yes. All our home improvement calculators are free to use with no sign up and no limit. The results appear as you type, and you can copy them or copy a link that keeps your numbers, so you can share an estimate with a partner or a tradesperson.
Do the calculators work in imperial units?
Yes. Most of our home improvement calculators have a Metric and Imperial switch. Lengths change to feet, areas to square feet and small sizes to inches. Paint stays in litres because that is how UK and EU tins are sold.
Which energy prices do the calculators use?
The default electricity and gas rates are the Ofgem price cap figures for 1 October to 31 December 2026. You can switch to EU, German or Irish averages from Eurostat, or type your own tariff from your bill for the most accurate answer.
Can I use a result to order materials?
You can use it to plan and to check quotes. Before you buy, compare the result with the coverage or pack size on the actual product, add sensible wastage, and for heating systems ask an installer for a full heat loss survey.
Do you store the numbers I type?
No. Our home improvement calculators run in your browser, so the measurements and readings you enter are not sent to our server. If you copy a link with your numbers, those values sit in the link itself and only go where you share it.
How do I report a wrong figure?
Use the report an error page and tell us the calculator, the inputs you used and the source you think is right. We check it against the original source, fix the page if needed, update the Checked date and record the change.