Celsius to Fahrenheit

Multiply by 9/5 and add 32. Doubling and adding thirty is the mental version and is close enough for weather — 20°C gives 70 against a true 68.

Temperature is the one conversion where a simple multiplication does not work, because the two scales have different zero points. That is also why −40 is the same number on both scales, the single point where they cross.

The rows below are the ones actually looked up: freezing, a comfortable room, body temperature at 37°C which is 98.6°F, and the oven settings. Note that fan ovens are conventionally set about 20°C lower than conventional ones for the same result, so a recipe's 180°C fan is 200°C conventional, or 392°F.

The formula

°F = (°C × 9/5) + 32

Celsius to Fahrenheit table

Celsius	Fahrenheit
-40	-40
0	32
10	50
20	68
30	86
37	98.6
100	212
180	356
220	428