At the Ofgem cap rate for 1 October to 31 December 2026, a microwave rated 800W costs about 2.8p a use and £20.49 a year when 8 minutes a time, 2 times a day.
| Per hour of running | 21.1p |
|---|---|
| Per use | 2.8p |
| Per day | 5.6p |
| Per year | £20.49 (78 kWh) |
Calculated at 26.32p per kWh, the capped electricity unit rate for 1 October to 31 December 2026 on a standard variable tariff paid by direct debit. Electricity carries no VAT in that period, so this is the full unit price. The 54.83p daily standing charge is not included, because you pay that whether or not anything is switched on.
Two things worth knowing about that figure. The cap limits the unit rate, not your bill, so using more still costs more. And it is a Great Britain average: the actual capped rate is set per region, so your own rate could move these numbers either way. It is on your bill.
Microwave has no thermostat cycling it on and off, so the running cost is simply the rated power multiplied by the time it is switched on. Short bursts of high wattage cost less than people expect.
Figures for microwave run from about 600W to 1200W. The wattage on the front is usually the cooking output, not the electrical input. A microwave sold as 800W typically draws around 1.2kW from the socket. Run times are short enough that it is one of the cheapest ways to heat food.
There is little to save on the cooking itself. If yours has a clock display, that draws a small amount continuously, which over a year can approach the cost of the cooking.
Confusing output wattage with input wattage. They differ by roughly a third.
Annual running cost against the appliances closest to it, on the same assumptions. The ordering surprises people: short bursts of very high wattage usually cost less than something modest left on for hours.
| Appliance | Per year |
|---|---|
| Air conditioner | £41.45 |
| Television | £38.43 |
| Hair dryer | £24.02 |
| Microwave | £20.49 |
| Vacuum cleaner | £14.41 |
Across a year, a microwave on these assumptions is about 3.1% of a typical annual electricity bill of £658.00 at these rates.
The figures here use the capped rate. If you are on a fixed tariff, or you want to add several appliances together, put your own unit rate into the energy cost calculator on the homepage.