Electricity Cost Calculator
Find out how much any electrical appliance costs to run. Enter the wattage, how many hours per day you use it, and your electricity rate — the default is the current Ofgem price cap unit rate.
How Electricity Cost Calculator works
How electricity cost is calculated
Electricity is charged per kilowatt-hour (kWh). One kWh is the energy used by a 1,000W device running for one hour. To calculate daily kWh: multiply wattage by hours per day and divide by 1,000. To calculate cost: multiply kWh by the unit rate in pence per kWh and divide by 100 to get pounds.
The Ofgem price cap unit rate
Ofgem sets a price cap each quarter that limits what energy suppliers can charge for a unit of electricity. As of Q1 2026, the capped unit rate is approximately 24.50p/kWh, with a standing charge of around 61p/day. The cap applies to typical households on default tariffs — if you are on a fixed tariff, your rate may differ. Check your energy bill for the exact rate.
Typical appliance wattages
Common appliance wattages: electric kettle 2,000–3,000W; microwave 700–1,200W; electric shower 7,000–10,500W; tumble dryer 2,000–2,500W; dishwasher 1,200–2,400W; fridge-freezer 100–400W; TV 30–200W; laptop 20–80W; LED light bulb 5–15W. The wattage is usually printed on the appliance or its packaging.
Reducing electricity bills
The most impactful changes are replacing high-wattage appliances with efficient alternatives (LED bulbs instead of incandescent), reducing run time of high-draw appliances (tumble dryers, electric showers, kettles), and avoiding standby power for devices that are rarely used. Running dishwashers and washing machines on eco modes and off-peak tariffs also reduces cost.
Frequently asked questions
How much does it cost to run a tumble dryer?
A typical tumble dryer uses 2,000–2,500W. At 24.5p/kWh, a 2,500W dryer running for 1 hour costs 2.5 kWh × 24.5p = approximately 61p per cycle. If you run it 5 times a week, that is about £3.05/week or £159/year. Heat pump dryers use roughly half the energy.
How much does it cost to leave a TV on standby?
Modern TVs typically draw 0.5–2W in standby. At 24.5p/kWh, 1W for 24 hours costs 0.024 kWh × 24.5p ≈ 0.6p per day or about £2/year. While small for one device, this adds up across all standby devices. Smart plugs with energy monitoring can help identify larger standby consumers.
What is a kWh?
A kilowatt-hour (kWh) is a unit of energy equal to one kilowatt (1,000 watts) of power used continuously for one hour. It is the standard unit on UK electricity bills. A 100W light bulb uses 0.1 kWh per hour, or 1 kWh after 10 hours. A kettle at 3,000W uses 1 kWh after 20 minutes.
How do I find out my electricity rate?
Check your electricity bill or your supplier's online account. The unit rate (in p/kWh) is listed separately from the standing charge. If you are on the default Ofgem-capped tariff, the rate changes quarterly. If on a fixed tariff, your rate is set until the deal ends.
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