How it works
- 01
Type a temperature
Plain numbers, decimals or a minus sign. The answer updates as you type.
- 02
Read the other scale
Kelvin is in the same list, and the swap button reverses the conversion.
- 03
Copy it
One tap copies the number. One decimal place suits most weather.
Conversion table
| Celsius | Fahrenheit | Celsius | Fahrenheit |
|---|---|---|---|
| -40 °C | -40.0 °F | 20 °C | 68.0 °F |
| -20 °C | -4.0 °F | 25 °C | 77.0 °F |
| -10 °C | 14.0 °F | 30 °C | 86.0 °F |
| 0 °C | 32.0 °F | 37 °C | 98.6 °F |
| 10 °C | 50.0 °F | 40 °C | 104.0 °F |
| 16 °C | 60.8 °F | 100 °C | 212.0 °F |
Why this one needs adding as well as multiplying
Most conversions are one multiplication. This one is not, because the two scales disagree about where zero is as well as how big a degree is. A Fahrenheit degree is five ninths of a Celsius one, and Fahrenheit puts freezing at 32 rather than 0. So the sum is multiply by 9, divide by 5, then add 32.
That offset is what makes negatives look odd. Minus 10 °C is 14 °F, not minus 14. The multiplication happens first and the 32 goes on last, which pulls this answer back above zero.
One point is the same on both scales: minus 40. It is where the two lines cross, and it is the quickest way to tell whether a converter is doing the offset at all. For a figure in your head, double it and add 30. That is close enough for weather, but it drifts badly at oven temperatures. At 200 °C it gives 430 °F instead of 392.
- The sum
- Times 9, divide by 5, add 32.
- Water
- Freezes at 0 °C, or 32 °F. Boils at 100 °C, or 212 °F.
- The same
- −40 °C and −40 °F are one temperature.
- Kelvin
- Celsius plus 273.15. No degree sign.