Electricity Usage Calculator UK
This electricity usage calculator shows how much electricity your appliances use and what they cost to run. Add each appliance’s power in watts and the hours a day you use it; the calculator turns that into kWh and prices it at the Ofgem Q4 2026 cap average of 26.32p per kWh, or your own rate.
How the electricity usage calculator works
Power in watts × hours of use ÷ 1,000 = kilowatt-hours (kWh), the unit on your bill. Multiply the kWh by your unit rate to get the cost. A 1,000-watt appliance used for one hour uses one kWh, so at 26.32p per kWh it costs 26.32p.
Why your bill is more than the appliances add up to
Your bill also carries a daily standing charge, 54.83p a day on the Q4 2026 cap average, which you pay however little you use. Appliances that cycle on and off, such as fridges, or that vary their power, such as washing machines, rarely draw their full rating all the time, so treat the result as an upper estimate for those.