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What The Microwave vs Oven Calculator Works Out
- Oven: the kilowatt-hours a typical electric oven uses for the dish, including preheat, multiplied by your unit rate. A jacket potato's 75-minute oven journey uses about 1.8 kWh, around 45p to 50p at the current Ofgem price cap rate (26.32p per kWh from October 2026, the default here), because the oven heats a steel cavity and the kitchen before any heat reaches dinner.
- Microwave: the same dish's microwave energy at your rate. The microwave couples energy to the food's water directly, so the same potato takes 0.15 kWh and about 4p.
- Verdict: the oven cost divided by the microwave cost, typically 10x to 15x. The oven keeps its genuine wins on browning, crisping and Maillard chemistry, which microwaves cannot perform.
- Saving per year (advanced): the per-dish difference multiplied by how often you cook it each week and 52 weeks. Three jacket potatoes a week saved from the oven is worth GBP 60 to GBP 70 a year.
- Portions per oven batch (advanced): divides the oven's fixed cost across everything cooked in the same run. A full three-shelf oven at six portions beats the microwave per portion, which is the batch-cooking case for the oven.
- Air fryer (advanced): energy for the same dish in an air fryer, default 0.35 kWh. It is functionally a small fast oven whose economics sit closer to the microwave for single portions.
- Microwave then oven (advanced): the hybrid method, default 0.6 kWh: about eight minutes of microwave then fifteen in a hot oven gives a crisp jacket potato at roughly a third of the oven-only cost and half the time.
- Gas oven (advanced): the same kilowatt-hours bought as gas at the current price cap rate. Gas is about a third of the price of electricity per unit, but a gas oven still heats the box, so the microwave usually stays ahead.
- Microwave wattage (advanced): packet timings assume 800W. The card scales the cooking time to your microwave's rated output: a 1,000W machine cooks in about 80% of the packet time for the same energy; a 650W one needs about 25% longer.