UK Heating Calculator
Estimate how much an electric heater costs to run using its wattage, your electricity unit rate and the number of hours you expect to use it. The calculator shows the maximum cost while the heater is drawing its rated power continuously.
Current reference rate: 26.32p/kWh is pre-filled as the average Ofgem electricity price-cap unit rate for Direct Debit from 1 October to 31 December 2026 in England, Scotland and Wales. Ofgem’s published electricity figure for this period excludes VAT because VAT has been removed from electricity bills from 1 October 2026 to 31 March 2027. Replace it with the unit rate shown on your own tariff for a more accurate result.
Last updated: October 2026. Ofgem’s next price cap announcement is scheduled for 25 November 2026, covering 1 January to 31 March 2027.
Electric heater running cost calculator
- Cost per hour
- £0.53
- Cost per day
- £1.58
- Cost per 7 days
- £11.05
- Cost per 30 days
- £47.38
- Energy used for selected period
- 180.00 kWh
- Cost for selected period
- £47.38
This is an upper-bound running-cost estimate. Many thermostatically controlled heaters cycle on and off after the room warms up, so actual electricity use can be lower than the continuous rated-power calculation. Room heat loss, thermostat setting and heater controls all affect real use.
How the heater cost calculation works
The calculator converts watts to kilowatts, then multiplies heater power by time and your electricity unit rate.
Running cost = heater power in kW × hours used × electricity price per kWh.
A 2,000W heater is a 2kW heater. At 26.32p/kWh, one hour of continuous full-power operation costs about 53p. If a thermostat switches the element off for part of the hour, actual consumption will be lower.
The calculation excludes the electricity standing charge because you normally pay that daily charge whether or not the heater is running.
Use the right wattage
If you are unsure what number to enter, check the appliance label or manual. Common portable electric heaters are often rated somewhere between a few hundred watts and around 2,000W or more.
See the Electric Heater Wattage Guide UK for help converting watts into kW and understanding what the rating means.
Why your real heater cost may be different
- Your tariff may be higher or lower than the Ofgem average.
- A thermostat may cycle the heater rather than drawing full power continuously.
- Timers and lower thermostat settings can reduce run time.
- A cold, draughty room may require more heating time than a well-insulated room.
- Time-of-use tariffs can have different prices at different times of day.
For practical controls and temperature guidance, see Best Heater Settings to Save Electricity UK.
Related heating and electricity tools
For a broader explanation of heater costs, use Heater Running Cost UK. For other appliances, use the Electricity Cost Calculator UK. For all tools, visit the Calculators hub. You can also browse the Heating hub or the Energy Bills hub.
Source for the default electricity rate
The pre-filled 26.32p/kWh figure is Ofgem’s average electricity unit rate for a standard variable tariff paid by Direct Debit in England, Scotland and Wales for 1 October to 31 December 2026. Ofgem’s published electricity figure for this period excludes VAT. Your actual tariff can differ, so use the rate on your bill.