Units
Air fryer converter and recipe scaler
About 20°C less and about 20% less time, plus scaled ingredients.
How to use it
- Enter the oven temperature in Celsius and the time in minutes.
- Tick the box if the recipe is already written for a fan oven. Otherwise the page takes off 20°C.
- For a recipe, enter the original servings and the new servings, or type a factor, then one ingredient per line.
The temperature and the time
A common kitchen rule is to set an air fryer about 20°C below a conventional oven and to cook for about 20% less time. A 180°C, 25-minute roast becomes 160°C and 20 minutes. If the recipe already says fan 160°C, leave the temperature and only shorten the time. This is guidance. It is not a tested conversion, and it does not tell you the food is cooked. Open the basket and check.
Gas marks and Fahrenheit are on the gas mark converter and the Celsius to Fahrenheit converter.
How quantities are rounded
Grams and millilitres under 10 keep one decimal place. From 10 they round to the nearest whole gram or millilitre. Kilograms and litres round to two decimal places. Teaspoons, tablespoons, cups and ounces round to the nearest quarter. Eggs round to the nearest half. A count such as “2 large onions” rounds to the nearest half below 10 and to a whole number from 10. A line with no quantity is left as written.
Cup weights for flour, sugar and butter are on the cups to grams converter. The rounding above is this page’s measuring rule, not a published standard.
Questions
Should I take 20°C off a fan-oven recipe?
No. Tick the fan-oven box. The page then keeps the temperature and still shortens the time by about 20%.
Is 20% less time exact?
It is a starting point. Dense food and a full basket often need longer. Check that the food is cooked.