Electricity Cost Calculator
Calculate electricity costs for any appliance based on usage and tariff.
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About the Electricity Cost Calculator
Electricity is priced per kilowatt-hour (kWh). A kilowatt-hour is the energy used by a 1,000-watt appliance running for one hour, or equivalently a 100-watt appliance running for 10 hours. Understanding how to calculate the running cost of any appliance helps you identify which devices are costing you the most and make informed decisions about energy efficiency upgrades.
UK electricity prices reached a peak of around 34p/kWh in early 2023 following the energy crisis, and have settled around 24–28p/kWh in 2024/25 under the Ofgem price cap. For comparison, the typical UK household uses about 2,700–3,100 kWh per year. A single electric shower (9.5 kW) running for 8 minutes uses roughly 1.3 kWh — at 28p/kWh, that's about 36p per shower, or over £130/year for a daily shower.
The biggest consumers of domestic electricity are typically: electric showers (7–10 kW), immersion heaters (3 kW), tumble dryers (2.5–5 kW), electric hobs (1.2–3 kW), washing machines (0.5–2.5 kW), dishwashers (1.2–2.5 kW) and electric ovens (2–3 kW). Standby power is much smaller but still adds up — the typical UK home wastes around £30/year on standby devices.
How it works
kWh consumed = (Wattage ÷ 1,000) × Hours used Cost = kWh × Price per kWh Annual cost = (Wattage ÷ 1,000) × Hours/day × 365 × Price/kWh
Where
WWattage — power rating of the appliance in watts (found on the label or manual)kWhKilowatt-hour — the billing unit; 1 kWh = 1,000 watts for 1 hourp/kWhPence per kilowatt-hour — your electricity tariff rateTips to improve your result
- 1.
Find your electricity rate on your bill under "unit rate" — it is different from the "standing charge" (a fixed daily amount). Rates vary by region and supplier.
- 2.
Energy-efficient appliances use significantly less power. An A-rated LED TV (50W) costs about 1/5th to run compared to an old plasma TV (250W) showing the same content.
- 3.
Smart plugs with energy monitoring (£15–£30 each) let you measure the actual wattage of any appliance, which is often lower than the maximum rating printed on the label.
- 4.
Time-of-use tariffs (like Octopus Go or Agile) offer cheap overnight electricity (sometimes below 7p/kWh). Running dishwashers and washing machines overnight can halve their running costs.
- 5.
Heat pumps use electricity but are 2–4× more efficient than electric heaters — for every 1 kWh of electricity, they deliver 2–4 kWh of heat. An air source heat pump at 28p/kWh effectively delivers heat at 7–14p/kWh.