Oven temperature conversion: °F, °C, gas mark

How it works

Formula: °C = (°F − 32) ÷ 1.8

Converting between °F and °C is exact: °C = (°F − 32) ÷ 1.8. Gas marks and the French thermostat are oven settings, not units: by convention each gas mark adds 25 °F (gas mark 4 = 350 °F), and each French thermostat step is 30 °C (thermostat 6 = 180 °C). Kitchen charts round the °C of these settings, sometimes loosely; the tool also shows the exact value.

• Wikipedia — Gas mark (table citing BBC Good Food and The Guardian)

Worked examples

• 350 °F in °C

  176.7 °C, which recipes round to 180 °C.

• 180 °C in °F

  356 °F: gas mark 4, French thermostat 6.

• 425 °F in °C

  218 °C, often written 220 °C.

Common mistakes

• Doubling °C to get °F: 180 °C = 360 °F.

  Multiply by 1.8 and add 32: 356 °F.

• Treating a chart's °C as an exact conversion.

  Gas mark 3 is 325 °F, exactly 162.8 °C, but charts print 170 °C.

• Assuming every oven runs true to its dial.

  Oven settings are approximate: an oven thermometer tells you what yours really does.

What the calculation leaves out

• Gas marks and the thermostat scale are rounded settings: each oven's real heat differs.
• For fan or convection ovens, many recipes suggest a lower temperature: follow your oven's manual.

Gas marks, °F and °C, with the French thermostat

Frequently asked questions