Converter
Degrees Fahrenheit to Degrees Celsius
1 °F is -17.2222 °C. Type any amount below and the answer follows as you type, on your device.
The answer follows what you type, rounded to six significant figures. Nothing is sent anywhere.
The formula
°C = °F × 0.555556 − 17.7778
Multiply the degree Fahrenheit figure by 0.555556, then subtract 17.7778.
The added number is there because the two scales do not start at the same place. That is why this conversion cannot be done with a single multiplication.
Worked example
How many degrees Celsius are in 10 degrees Fahrenheit?
10 °F → -12.2222 °C
Multiply 10 by 0.555556, then subtract 17.7778. The answer is -12.2222 °C.
Quick reference
The common values, rounded to six significant figures.
| degrees Fahrenheit (°F) | degrees Celsius (°C) |
|---|---|
| 0 | -17.7778 |
| 5 | -15 |
| 10 | -12.2222 |
| 15 | -9.44444 |
| 20 | -6.66667 |
| 25 | -3.88889 |
| 30 | -1.11111 |
| 37 | 2.77778 |
| 100 | 37.7778 |
When you need this
Australian and British thermometers read Celsius, so this is the direction to use when an American oven setting or a Fahrenheit weather report needs to mean something on a local oven.
The factor above is the exact legal definition of each unit, not a rounded one, so the answers stay right at any size. Nothing here is sent to a server: the conversion runs in the page.