1 fahrenheit = -17.222222 °C
1 °F = -17.2222 °C · type math like (12*4)+6.5
Fahrenheit to Celsius is what people outside the US need when reading American recipes, weather reports or appliance manuals. American bakers sharing recipes abroad and travellers checking a US forecast use it daily.
Weather is the other everyday use. A US forecast high of 95 °F is 35 °C, hot enough for heat advisories in most climates, while a winter low of 20 °F is −6.7 °C. Wind chill and heat index tables published by the US National Weather Service are in Fahrenheit, so travellers often need to translate them.
Home brewing and candy making rely on precise temperatures. A mash rest at 152 °F is 66.7 °C, and the soft-ball stage for fudge at 235 °F is 112.8 °C. Being off by a few degrees changes the result, so it is worth converting exactly rather than using the subtract-30-and-halve shortcut.
US appliance manuals also use Fahrenheit. A water heater set to 120 °F is at 48.9 °C, the temperature recommended in the US to reduce scald risk.
Car manuals in the US list coolant and oil temperatures in Fahrenheit. A normal operating temperature of 195–220 °F is 90.6–104.4 °C.
Sous vide cooking guides in the US often use Fahrenheit. A steak cooked medium-rare at 131 °F is 55 °C, and chicken breast at 145 °F is 62.8 °C.
To check an answer, use anchor points: 50 °F is 10 °C, 68 °F is 20 °C, 86 °F is 30 °C, and 212 °F is 100 °C. Every 18 °F step equals 10 °C. If your result for a warm day is above 50 °C, you forgot to subtract 32 first. Oven temperatures usually round to the nearest 5 or 10 °C, since dials in metric countries rarely show finer steps than that.
°C = (°F − 32) × 5/9
Reverse: 1 °C = 33.8 °F.
Convert a room temperature of 72 °F to Celsius.
Answer: 72 °F = 22.2 °C.
| °F | °C |
|---|---|
| -40 °F | -40 °C |
| -30 °F | -34.444444 °C |
| -20 °F | -28.888889 °C |
| -10 °F | -23.333333 °C |
| 0 °F | -17.777778 °C |
| 1 °F | -17.222222 °C |
| 2 °F | -16.666667 °C |
| 3 °F | -16.111111 °C |
| 4 °F | -15.555556 °C |
| 5 °F | -15 °C |
| 6 °F | -14.444444 °C |
| 7 °F | -13.888889 °C |
| 8 °F | -13.333333 °C |
| 9 °F | -12.777778 °C |
| 10 °F | -12.222222 °C |
| 11 °F | -11.666667 °C |
| 12 °F | -11.111111 °C |
| °F | °C |
|---|---|
| 13 °F | -10.555556 °C |
| 14 °F | -10 °C |
| 15 °F | -9.4444444 °C |
| 16 °F | -8.8888889 °C |
| 17 °F | -8.3333333 °C |
| 18 °F | -7.7777778 °C |
| 19 °F | -7.2222222 °C |
| 20 °F | -6.6666667 °C |
| 25 °F | -3.8888889 °C |
| 30 °F | -1.1111111 °C |
| 40 °F | 4.4444444 °C |
| 50 °F | 10 °C |
| 75 °F | 23.888889 °C |
| 100 °F | 37.777778 °C |
| 250 °F | 121.11111 °C |
| 500 °F | 260 °C |
| 1 000 °F | 537.77778 °C |
(350 − 32) × 5/9 = 176.7 °C, so recipes abroad round it to 180 °C or 175 °C.
A thermostat at 72 °F is 22.2 °C.
A freezer at 0 °F is −17.8 °C.
350 × 5/9 − 32 = 162.4, which is wrong. Subtract 32 first, then multiply by 5/9 for 176.7 °C.
Halving after subtracting 32 understates. For 212 °F it gives 90 °C instead of 100 °C.
A change of 9 °F is a change of 5 °C. Do not subtract 32 when converting a difference.
One Fahrenheit degree is 5/9 of a kelvin. Water freezes at 32 °F and boils at 212 °F at standard pressure.
Origin. Introduced by Daniel Gabriel Fahrenheit in 1724, who also built the first reliable mercury thermometers.
Used today. US weather, cooking, thermostats and pool temperatures.
A degree Celsius is the same size as one kelvin. The Celsius scale is defined from the Kelvin scale as °C = K − 273.15, so water freezes close to 0 °C and boils close to 100 °C at sea-level pressure.
Origin. Proposed by Anders Celsius in 1742 and adopted as the metric temperature scale.
Used today. Weather and cooking across most of the world, and the everyday scale in science.
Subtract 30 and halve. 80 °F gives 25 °C; the exact answer is 26.7 °C.
204.4 °C, typically written as 200 °C or gas mark 6 in UK recipes.
0 °C, the freezing point of water.
−17.8 °C, colder than water's freezing point.