Show the formula and working
This free slow cooker running cost calculator tells households in the UK, Ireland, Germany, the Netherlands and France what a slow cooker costs per meal, per portion and per year. Enter the power rating and cooking time, or a kWh figure measured with a plug-in energy monitor, and your unit rate in pence or cents.
Quick answer: A slow cooker running cost calculator multiplies the watts by the cooking hours and your unit rate. A 210 W slow cooker running for 8 hours uses at most 1.68 kWh, which costs 44.22p at 26.32p per kWh, or 11p a portion for four people. Real use is usually lower.
What Is a Slow Cooker Running Cost Calculator?
A slow cooker running cost calculator is a tool that converts a slow cooker’s power and cooking time into a cost per meal, per portion and per year at your electricity price.
The formula in plain words: energy per cook equals the power rating in watts times the hours, divided by 1,000. Cost per cook equals the energy times the unit rate, cost per portion divides that by the portions, and cost per year multiplies it by the cooks per week and by 52. Because the rating is the most the cooker can draw, this gives an upper limit; a measured kWh figure gives the real cost.
How Do You Use the Slow Cooker Running Cost Calculator?
- Choose the Energy figure to use. If you have not measured it, keep the power rating option.
- Enter the Slow cooker power rating from the base and the Cooking time, or the Measured kWh per cook from an energy monitor.
- Enter the Cooks per week and Portions per cook.
- Enter the Electricity unit rate from your bill and choose pounds or euros with the currency switch.
- Read the cost per cook, per portion and per year, then open “Show the formula and working” to see the sums.
How Much Does It Cost to Run a Slow Cooker?
A typical 3.5 litre slow cooker costs at most about 44p for an 8 hour cook at 26.32p per kWh. The Crock-Pot CSC025X 3.5 litre model is listed at 210 W, and 210 W for 8 hours is 1.68 kWh. The unit rate is the Great Britain direct debit average under the Ofgem price cap from 1 October to 31 December 2026. The element switches on and off once the pot is hot, so the cost you actually pay is usually lower.
Is a Slow Cooker Cheaper Than an Oven?
A slow cooker usually costs less than running an electric oven for the same long, slow dish. Over 8 hours, a 210 W slow cooker draws at most 1.68 kWh, while an oven’s element of a few kilowatts would use that in well under an hour at full power. For short cooking times the gap is smaller, and an air fryer or microwave can be cheaper still; the air fryer running cost calculator shows that side.
Does the Low Setting Use Less Electricity?
The low setting usually draws less power than high, but the food cooks for longer, so the total energy can end up similar. The rating on the base is the most the cooker draws. To find the real figure for your cooker and recipe, plug it into an energy monitor for one cook, then choose Measured kWh per cook and enter the reading.
Is Slow Cooked Food Safe to Eat?
Yes, if the food is cooked until steaming hot all the way through. Food Standards Agency guidance gives 70 °C for 2 minutes at the centre as the standard, and says to follow the appliance instructions for slow cookers. Check meat with a food thermometer, keep the lid on, and cool leftovers quickly and reheat them only once.
Slow Cooker Running Costs by Power and Time
Upper limit cost per cook (rated power x hours) at 26.32p per kWh.
| Power rating | 4 hours | 6 hours | 8 hours | 10 hours |
|---|---|---|---|---|
| 150 W | 15.79p | 23.69p | 31.58p | 39.48p |
| 210 W | 22.11p | 33.16p | 44.22p | 55.27p |
| 250 W | 26.32p | 39.48p | 52.64p | 65.80p |
| 320 W | 33.69p | 50.53p | 67.38p | 84.22p |
Worked Example: A Weekly Stew in Pounds and Euros
Example: a 210 W slow cooker running for 8 hours, twice a week, making 4 portions each time, at 26.32p per kWh. These are the default inputs.
- Energy per cook: 210 W x 8 h / 1,000 = 1.68 kWh (upper limit).
- Cost per cook: 1.68 kWh x 26.32p = 44.22p, or 11.05p a portion.
- Cost per year: 44.22p x 2 x 52 = £45.99.
If an energy monitor showed 1.2 kWh for the same stew, choose Measured kWh per cook: the cost falls to 31.58p. In euros, switch the currency and enter an example rate of 35 in Electricity unit rate: the rated figure gives 58.8c per cook and €61.15 a year. To scale the recipe for more people, use the recipe scaler.
Slow Cooker Running Cost Calculator FAQs
How many watts does a slow cooker use?
Home slow cookers are rated at a few hundred watts, far below an oven or hob. The Crock-Pot CSC025X 3.5 litre model is listed at 210 W, and larger pots are usually rated higher. The figure is printed on the base or in the manual.
Is it safe to leave a slow cooker on all day?
Yes, slow cookers are designed to run unattended for hours. Stand it on a heat resistant surface away from the edge, keep the flex tidy, follow the maker’s instructions, and make sure the food is steaming hot before you serve it.
Does the keep warm setting cost much?
Keep warm uses less power than cooking, but it adds up over several hours. Food kept hot should stay at 63 °C or above, the top of the 8 °C to 63 °C danger zone in which bacteria grow fastest. If dinner is hours away, it is often better to cool, chill and reheat.
How do I measure my slow cooker’s energy use?
Plug it into a plug-in energy monitor, reset the reading, cook as normal and read the kWh at the end. Enter that figure in Measured kWh per cook to get the real cost, which is usually lower than the rating suggests.
Is a bigger slow cooker more expensive to run?
A bigger pot usually has a higher rating, so it costs more per hour, but it cooks more portions. Compare the cost per portion: a half full large pot is less efficient than a full smaller one.
Can I put frozen food in a slow cooker?
Follow the maker’s instructions. Many advise defrosting meat fully in the fridge first, because frozen food slows heating and keeps the pot in the temperature range where bacteria grow for longer. Always cook until steaming hot throughout.
For more appliance costs, see the energy bill calculators.
Checked October 2026. Sources: Energy price cap unit rates and standing charges (Ofgem), Cooking your food (Food Standards Agency, GOV.UK).