Oven Temperature Converter

Enter a temperature in Celsius or Fahrenheit, or a British gas mark, and read across the standard oven chart: the matching value in the other two scales plus the descriptive name cooks use, from very cool at gas ¼ up to very hot at gas 9.

The chart is a set of conventions, not a conversion, and that is the thing to understand before you trust it. 180 °C is exactly 356 °F, but every cookbook pairs it with 350 °F and gas 4, because those are the round numbers ovens are marked with. The rounding does not even go the same way each time: 200 °C is exactly 392 °F and the chart says 400, while 220 °C is exactly 428 °F and the chart says 425. So this tool snaps your input to the nearest row rather than doing the arithmetic, which is what makes it agree with the recipe in front of you instead of with a calculator.

The reason the Fahrenheit column is the regular one is that the gas scale was defined in Fahrenheit. Gas 1 is 275 °F and every whole mark adds exactly 25 °F, which is why the column runs 275, 300, 325 and so on without a break, while the Celsius column has to limp along in steps of 10 and 20 — 170, 180, 190, 200, then 220. The two fractional marks below 1, ¼ and ½, continue the same 25 °F spacing downwards to 225 and 250 °F.

What no chart can tell you is where the heat actually is. A fan oven moves air, so it cooks as though it were about 20 °C hotter than the dial says, which is why fan recipes quote a lower number for the same result. Domestic thermostats also swing by 10–15 °C either side of the setpoint as the element cycles, and the top of the oven is hotter than the bottom. An oven thermometer settles more arguments than any chart.