Oven Temperature Conversion Calculator: Gas Mark, Fan, Celsius and AGA

A recipe gives one number, your cooker shows another. Type any oven temperature you have, in gas mark, conventional Celsius, fan Celsius or Fahrenheit, and this gives you all of the others at once, plus the matching AGA oven. The trap most people hit is the fan oven: a fan circulates hotter air, so it runs roughly 20C above a conventional oven at the same setting, which is why fan recipes ask you to drop the temperature.

Gas mark and Fahrenheit always refer to a conventional (non fan) oven, so converting to or from a fan setting applies the 20C reduction automatically. The AGA oven is matched to the conventional temperature, since an AGA roasting oven and baking oven run at fixed heats rather than a dial.