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WattWorth

Electricity cost calculator

Enter an appliance’s power and how long it runs to see what it costs per hour, day, month and year. It uses the electricity price where you live, which you can change to the rate on your bill.

A month of running costs

£8.01 a month

26.3p for each hour it runs, and £96.07 a year.

On the label or in the manual. A kilowatt (kW) is 1,000 W.

Standby, thermostats and off-peak use

Heaters and fridges switch on and off to hold a temperature. 100% for anything that runs flat out.

Drawn while plugged in and not running. Usually under 1 W.

Electricity price

26.32p/kWh in the United Kingdom

Default Ofgem, 1 Oct – 31 Dec 2026.
Running cost, energy and emissions by period
PeriodCostEnergyCO2e
An hour of use26.3p1.00 kWh217 g
A day, on average26.3p1.00 kWh217 g
A month£8.0130.4 kWh6.6 kg
A year£96.07365 kWh79.4 kg

How we calculated this

Energy is power multiplied by time. 1,000 W running for an hour uses 1.00 kWh.

A day is the average across the week, a month is a twelfth of a 365-day year.

Electricity costs 26.32p/kWh. That is the published figure for the United Kingdom, 1 Oct – 31 Dec 2026, from Ofgem. Average for England, Scotland and Wales, paying by Direct Debit. No VAT on electricity from 1 October 2026 to 31 March 2027.

Standing charges are left out: you pay them whether or not the appliance runs.

Emissions use 0.217 kg CO2e per kWh, the lifecycle intensity of electricity generated in the United Kingdom in 2025, from Ember, via Our World in Data. Lifecycle means building the power stations and supplying their fuel are counted too. It is the grid’s average, not the particular power station an extra appliance brings on.

Your prices

Every calculator uses these. They are saved on this device and nowhere else.

Pick where you live for your local prices.

Electricity

Default Ofgem, 1 Oct – 31 Dec 2026.

Default Ofgem, 1 Oct – 31 Dec 2026.

Gas

Default Ofgem, 1 Oct – 31 Dec 2026.

Default Ofgem, 1 Oct – 31 Dec 2026.