How much does an electric oven cost to run?
A 2.5kW electric oven costs up to 66p an hour at the Ofgem cap rate of 26.32p/kWh if the element never switches off. Real cooking is cheaper, because the thermostat cycles once the oven is hot. With a 10-minute preheat and then about 60% on-time, a 45-minute bake costs about 41p.
Prices last checked: 26 September 2026 · Source: Ofgem energy price cap, 1 October to 31 December 2026 · Great Britain average, standard variable tariff, paid by Direct Debit
Oven cost per cook
Built-in single ovens are typically rated somewhere around 2–3.5kW. The table assumes a 2.5kW oven, a 10-minute preheat at full power, then the element on 60% of the time. The 60% is an assumption for illustration.
| Cook | Cooking time | Energy incl. preheat | Cost |
|---|---|---|---|
| Oven chips / pizza | 20 min | 0.92 kWh | 24p |
| Traybake or bake | 45 min | 1.54 kWh | 41p |
| Roast chicken | 1 h 30 min | 2.67 kWh | 70p |
| Sunday roast, 2 h 30 min total | 2 h 30 min | 4.17 kWh | £1.10 |
What drives an oven's cost
- Preheat. Getting a large, cold, metal box up to 200°C is a big part of a short cook. For a 20-minute pizza, the preheat can use nearly as much energy as the cooking.
- Door opening. Each look lets out hot air, and the thermostat has to make it up.
- Empty space. One tray in a large oven costs the same to heat as three trays.
- Fan vs conventional. Fan ovens usually cook at a lower set temperature than conventional ovens (recipes often suggest around 20°C lower), which cuts the heat loss.
Cheaper options for smaller meals
Air fryer
For one or two portions, an air fryer is usually much cheaper: little or no preheat, a small cavity and a lower rating. See air fryer costs.
Microwave
For reheating and steaming vegetables, a microwave is typically the cheapest appliance. Its power goes into the food rather than into heating a box.
Slow cooker
For stews and casseroles, a slow cooker uses a fraction of the oven's power over the same meal.
Batch the oven
If the oven is on anyway, fill it. Roast the vegetables for tomorrow alongside tonight's dinner and the extra cost is small.
Common mistakes
- Rated watts × total time. That's the worst case. After the preheat, the element cycles.
- Preheating far longer than needed. Many ovens reach temperature well before the ten minutes people often allow. Some have an indicator light.
- Using the main oven for one small dish when a smaller top oven or an air fryer would do.
Limits of this estimate
The duty-cycle figures are illustrative assumptions, not measurements of a particular model. Costs use the Ofgem cap average unit rate for Great Britain, Direct Debit, standard variable tariff.
Frequently asked questions
How much does it cost to run an electric oven for an hour?
At full power, a 2.5kW oven costs about 66p an hour and a 3.5kW oven about 92p. Once it's hot and cycling, the average is lower.
How much does a Sunday roast cost to cook in an electric oven?
Using the assumptions above, about £1.10 for 2½ hours of cooking plus the preheat.
Is a fan oven cheaper to run?
Usually, because it can cook at a lower temperature and heats more evenly. The difference per meal is modest.