Heater running cost calculator
Pick a heater or type in its wattage, say how long you use it, and see what it costs per hour, day, week and month. It starts at the UK price cap rate of 26.32p per kWh (1 October to 31 December 2026), and you can change the rate to match your bill.
Work out your cost
Pick a heater or type in the wattage from its rating plate. Everything updates as you type.
That is 2.00 kWh an hour and 8.00 kWh a day. A month is the weekly cost × 52 ÷ 12. Excludes the daily standing charge.
Choosing one? See our oil-filled radiators guide.
How it's worked out
Cost per hour is the wattage divided by 1,000, multiplied by your unit rate, then multiplied by how hard the heater works. For example, a 2,000W radiator running flat out at 26.32p per kWh uses 2kWh an hour and costs about 53p.
The day, week and month figures multiply that by your hours per day and days per week. The monthly figure is the weekly cost × 52 ÷ 12. Standing charges are not included.
Rate source: Ofgem energy price cap, average Direct Debit electricity unit rate (England, Scotland and Wales).
Common questions
How do I work out what an electric heater costs to run?
Divide the wattage by 1,000 to get kilowatts, then multiply by your unit rate. A 2,000W heater at 26.32p per kWh costs about 53p for every hour it runs flat out.
What electricity rate does the calculator use?
It starts with the Ofgem price cap average unit rate of 26.32p per kWh for 1 October to 31 December 2026. You can type in your own rate from your bill if yours is different.
Does the cost include the standing charge?
No. The standing charge is a fixed daily amount you pay whether the heater is on or not, so it is left out to show only the cost of running the heater itself.
What does the "how hard it works" slider do?
Heaters with a thermostat switch off once the room is warm, then cycle on and off. Setting the slider below 100% gives a rough estimate of that. How much a heater cycles depends on the room, insulation and outside temperature, so treat it as a guide.
Is an oil-filled radiator cheaper to run than a fan heater?
Not per hour at the same wattage. A 2kW oil-filled radiator and a 2kW fan heater use the same electricity while running. Oil-filled radiators hold heat and release it slowly, which some people find more comfortable, but the running cost per hour is the same.
Why are heated clothes airers so cheap to run?
Most bar-style airers use between 100W and 300W, a fraction of a 2kW heater. At the price cap, a 300W airer costs only a few pence an hour.
How is the monthly figure worked out?
It takes the weekly cost and multiplies it by 52 weeks, then divides by 12 months. It assumes you use the heater the same way every week.
Where do the preset wattages come from?
Most presets match wattages of products in our buying guides. The fan heater preset is a typical 2kW figure rather than one specific model. Check the label or listing of your own heater for its exact wattage.
Will I pay exactly this amount?
Probably not exactly. Your cost depends on your tariff, region, the setting you use and how long the thermostat keeps the heater running. The calculator gives a sensible estimate to compare options.