How the three temperature scales line up, and why fan ovens need special treatment.
Oven temperature is written three different ways around the world, and getting it wrong is the fastest route to a burnt or underbaked result. Here’s how Fahrenheit, Celsius and gas marks line up — and why fan ovens need special treatment.
The United States uses Fahrenheit. Most of the world uses Celsius. British recipes often use gas marks, a numbered scale where gas mark 4 is the everyday baking temperature of about 350°F / 177°C. To convert Celsius to Fahrenheit, multiply by 9/5 and add 32; our Oven Temperature Converter shows all three at once.
A fan (or convection) oven circulates hot air, so it cooks more efficiently than a conventional oven at the same dial setting. If a recipe was written for a conventional oven and yours is fan-forced, it can brown too fast. The fix: lower the temperature by about 20°C (25°F), or shorten the time by roughly 10%. Many recipes now list both.
Ovens are often off by 10–25 degrees, so an inexpensive oven thermometer is a worthwhile check. And for anything roasted, internal temperature — see our cooking temperatures tool — is the honest measure of doneness.