Appliance running-cost calculator
Work out how much it costs to run any electrical appliance, from its power rating, how often you use it and your electricity price.
Result
Cost per year
Cost per week
How to use this tool
- Check the appliance's power rating in watts — usually on a label on the back or base, or in its manual.
- Enter how many hours it runs per use, and how many times a week you use it.
- Enter your electricity price per kWh from your bill or tariff.
- Read the estimated cost per week and per year; this tool does not report a separate cost per hour.
Assumptions
- Assumes the entered power is drawn continuously for all entered active-use hours. A rated/maximum wattage is not the same as measured average consumption; cycling and variable power can lower energy used.
- Uses the single electricity unit price you enter, displayed in GBP (£/kWh); no live tariff or currency conversion is applied. Standing charges, time-of-use rates and standby consumption are excluded.
Sources & reference data
Technical details: what the fields mean
- Power rating
powerWatts - Enter the power draw in watts for the operating mode you want to estimate. The label may show maximum or rated power, which can exceed average draw when a device cycles or varies its output.
- Hours per use
hoursPerUse - How long the appliance runs each time you use it.
- Uses per week
usesPerWeek - How many times a week you use it.
- Electricity price
pricePerKwh - Your electricity price per kWh — check a recent bill.
Methodology
Energy per week (kWh) = power (kW) × hours per use × uses per week. Cost per week = energy × your entered price per kWh. Cost per year = cost per week × 52; these are weekly and annual estimates, not an hourly result or a full bill.
Worked example
Illustration: 1000W input, 1 hour/use, 7 uses/week, entered rate £0.27/kWh
Inputs: Power rating: 1000 W, Hours per use: 1 hours, Uses per week: 7, Electricity price: £0.27/kWh
Result: £1.89/week, £98.28/year; this assumes continuous 1000W draw and is not a quoted tariff or measured appliance cost.
2kW plug-in heater on full for 3 hours every evening, entered rate £0.27/kWh
Inputs: Power rating: 2000 W, Hours per use: 3 hours, Uses per week: 7, Electricity price: £0.27/kWh
Result: £11.34/week, £589.68/year if run like this all year. Most people only heat for part of the year — divide by 52 and multiply by the weeks you actually use it. A heater with a thermostat cycles off once the room is warm, so real use is often lower.
Practical guidance
- For appliances that cycle on and off (fridges, thermostatic heaters), this gives an upper-bound estimate — actual usage is often lower.
- Compare a few appliances using this calculator to spot which ones actually dominate your bill — it's often not the ones people assume.
- For a measured rather than rated figure, a plug-in energy monitor shows the actual kWh an appliance used over a day or week; divide by the hours it ran to get its real average power, and enter that instead of the label wattage.
Common mistakes
- Confusing an appliance's peak/startup power with its typical running power, which can overstate the cost for motor-driven appliances.
- Forgetting standby power for appliances left plugged in — this calculator only covers active use.
FAQs
How do I find an appliance's power rating?
Check the label on the back or base of the appliance, or its manual — it's usually given in watts (W) or kilowatts (kW).
Does this include standby power?
No — this calculates active running cost only. Standby power for appliances left plugged in is a separate, usually much smaller, cost.
Why is my real bill different from the estimate?
The label wattage is often a maximum, many appliances cycle on and off, and your bill also includes a daily standing charge that this tool deliberately leaves out. Use a measured wattage and your actual unit rate for the closest estimate.
Which electricity price should I use?
The unit rate (p/kWh) from your bill or supplier account. Ofgem publishes the current price-cap unit rates for standard variable tariffs if you need a reference figure.
Last reviewed: 2026-10-11
A straightforward power × time estimate — real-world usage can differ for thermostatically controlled or variable-power appliances.
This tool provides an indicative estimate, based on the assumptions stated above.
Theme and tool preferences, along with saved and recently used lists, are stored only in this browser.