About the Convection Oven Converter
This convection oven converter adapts recipe temperatures and times between a conventional (thermal, top-and-bottom heat) oven and a convection or fan oven. Enter the temperature and time the recipe gives, choose which way you are converting, and pick whether to lower the temperature or shorten the time. It returns the new oven setting, the cooking time and the point at which to start checking for doneness.
A convection fan blows hot air over the food, stripping away the cool layer of air that surrounds it, so food browns and cooks faster at the same temperature. The standard US advice — repeated in many oven manuals — is to reduce the temperature by 25°F, or keep the temperature and reduce the time by about 25%. In Celsius, UK and European recipes conventionally use a 20°C lower setting for fan ovens (180°C becomes 160°C fan), which is what the calculator uses when you choose °C.
Lowering the temperature works best for cakes, breads, cookies and anything that needs to rise or set evenly. Shortening the time suits roasts, vegetables and other food you want browned and crisp. Many newer ovens have an “auto convection conversion” setting that already lowers the temperature — if yours does, enter the recipe temperature directly and don’t convert twice.
With the default inputs, the set the oven to is 325. Change any value above to recalculate instantly.
How to use the convection oven converter
- 1Enter the temperature and time from the recipe and choose °F or °C.
- 2Pick the direction: conventional to convection, or the reverse.
- 3Choose to change the temperature (baking) or the time (roasting).
- 4Set the oven to the new temperature and start checking at the time shown.
Formula and method
Convection ovens transfer heat faster because moving air keeps fresh hot air in contact with the food. The two standard ways to compensate are to lower the temperature by about 25°F — the common US rule, about 14°C — or to keep the temperature and cut the time by roughly 25%. For Celsius recipes the calculator uses the 20°C fan-oven offset printed on UK and European recipes and packaging. New temperatures are rounded to the nearest 5 degrees to match oven dials.
Converting the other way reverses the adjustment: add 25°F (20°C), or divide the time by 0.75. The “start checking” time is 75% of the cooking time when converting to convection, because results vary between ovens, fans and pan types.
- T
- Recipe temperature
- t
- Recipe cooking time in minutes
Worked examples
Cake at 350°F for 40 minutes
Lowering 350°F by 25°F gives 325°F on convection bake. Keep the 40-minute time but start checking at 30 minutes.
Roast chicken at 425°F for 80 minutes, time method
Keeping 425°F and cutting the time by 25% gives 60 minutes; begin checking the thigh temperature at about 45 minutes.
180°C recipe in a fan oven
For Celsius recipes the usual fan-oven offset is 20°C, so 180°C becomes 160°C fan (about 320°F), with the same 25-minute time. The equivalent for a gas oven is gas mark 4.
Frequently asked questions
How do I convert a recipe to a convection oven?+
Either lower the temperature by 25°F (about 15–20°C) and keep the same time, or keep the temperature and reduce the time by about 25%. Lowering the temperature is better for baking; cutting the time is better for roasting.
What is 350°F in a convection oven?+
Set a convection oven to 325°F for a recipe that calls for 350°F in a conventional oven, and start checking about three-quarters of the way through the original time.
Is a fan oven the same as a convection oven?+
Yes. “Fan oven” is the usual UK and European name and “convection” the US name for an oven with a fan circulating the hot air. A “true” or European convection oven also has a heating element around the fan.
What 180°C is in a fan oven?+
British and European recipes usually reduce fan-oven temperatures by 20°C, so 180°C conventional becomes 160°C fan. Many recipes print both: “180°C / 160°C fan / gas 4”.
When should I not use convection?+
Avoid the fan for delicate batters and custards such as soufflés, cheesecakes and some sponge cakes, which can set unevenly or form a crust too early. Use conventional bake for those.