Fan Oven Temperature Conversion

180 °C (conventional recipe) is 160 °C, gas mark 4.

Try your own numbers

From

Temperature

For a gas mark, type 1/4, 1/2 or a number from 1 to 9.

The recipe is written for a

Conventional ovenFan oven

My oven is a

Conventional ovenFan oven

Assumptions (editable)

Fan oven reduction, °C

°C

Fan oven reduction, °F

°F

A fan oven is set lower than a conventional oven for the same recipe. 20 °C is the usual figure (Which?) and 25 °F the usual US rule of thumb. Both are editorial rules of thumb, and 20 °C is 36 °F, so they are not the same size. Many ovens adjust automatically. Check your manual.

Set your oven to160 °C

Exact in °C160 °C

Exact in °F320 °F

Nearest gas markGas mark 4 (180 °C)

The recipe is for a conventional oven and yours is a fan oven, so 20 °C comes off: 180 − 20 = 160 °C. 160 °C × 9 ÷ 5 + 32 = 320 °F. The dial value is rounded to the nearest 10 °C or 25 °F.

Ovens vary, so use an oven thermometer to check.

Fig. 1 The converted oven temperature.

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Every formula is tested against worked examples. How we check

Gas mark	Conventional °C	Conventional °F	Fan °C	Fan °F
¼	110 °C	225 °F	90 °C	200 °F
½	120 °C	250 °F	100 °C	225 °F
1	140 °C	275 °F	120 °C	250 °F
2	150 °C	300 °F	130 °C	275 °F
3	160 °C	325 °F	140 °C	300 °F
4	180 °C	350 °F	160 °C	325 °F
5	190 °C	375 °F	170 °C	350 °F
6	200 °C	400 °F	180 °C	375 °F
7	220 °C	425 °F	200 °C	400 °F
8	230 °C	450 °F	210 °C	425 °F
9	240 °C	475 °F	220 °C	450 °F

Fig. 2 Common oven temperatures on every scale, with the fan setting. Gas marks are for conventional ovens.

Last checked 11/11/2026. Sources: Which?: Oven temperature conversion table (gas marks 1 to 9 with fan temperatures; fan ovens about 20 °C lower); Wikipedia: Gas mark (gas marks ¼ and ½; marks rise 25 °F each; prints 170 °C for gas mark 3).