Electricity Cost Calculator UK
Work out how much electricity costs in the UK using watts, daily hours, number of days and your unit rate in pence per kWh. Use it as an appliance running cost calculator for heaters, tumble dryers, TVs, PCs and other home devices.
Formula: kWh = watts / 1000 x hours x days. Cost = kWh x unit rate.
Watts vs kilowatt-hours
Watts measure power at a moment. Kilowatt-hours measure energy used over time, which is what your electricity bill charges for. A 1,000 watt appliance running for one hour uses 1 kWh.
Appliances that cycle on and off
Fridges, freezers, heat pump dryers and some heaters do not draw their maximum wattage all the time. For those devices, a plug-in energy meter or smart plug gives a better long-run estimate.
Use your actual tariff
The default price is only a starting point. Replace it with your own pence-per-kWh electricity rate, or run the calculator twice to compare peak and off-peak tariffs.
From electricity cost to bigger decisions
Once you know a device cost, compare transport with the electric car charging cost calculator, heating with the heat pump cost calculator, or solar value with the solar calculator payback tool.
Electricity cost FAQ
Does this include standing charges?
No. This calculator estimates usage cost only, not fixed daily standing charges.
Where do I find watts?
Many appliances show watts on a label, manual or product specification page.
Can I use this as a UK appliance running cost calculator?
Yes. Enter the appliance wattage, daily use and your electricity price in pence per kWh to estimate the cost in pounds.
Does this work for heaters, tumble dryers and gaming PCs?
Yes. Any device with a known wattage can be estimated, although cycling appliances may use less than their maximum rating over time.
How do I calculate electricity cost per kWh in the UK?
Convert watts to kilowatts, multiply by hours used, then multiply the kWh by your unit rate. A 1,000 watt appliance running for 2 hours uses 2 kWh.
Can this help estimate an electricity bill?
It can estimate the usage part of a bill for one appliance or device. Add several appliance estimates together for a rough household electricity usage calculator.