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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.

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:

1. Measure in metres to two decimal places, or switch to imperial before you type.
2. Measure each wall or floor area separately in an L shaped room, then add them together.
3. Use the coverage or pack size printed on the product you will actually buy.
4. Enter your own tariff from your latest bill rather than an average.
5. Add a little extra for wastage on awkward rooms, and buy materials from the same batch.
6. 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.

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