Temperature
Convert degree Fahrenheit (°F) to degree Celsius (°C). Temperature scales are affine, not just scaled — converting requires an offset as well as a factor, which is why °C and °F don't share a zero.
1 °F = -17.22222 °C
To convert degree Fahrenheit to degree Celsius, apply °C = °F × 0.5555556 − 17.77778.
| °F | °C |
|---|---|
| 1 | -17.22222 |
| 2 | -16.66667 |
| 5 | -15 |
| 10 | -12.22222 |
| 25 | -3.888889 |
| 50 | 10 |
| 100 | 37.77778 |
| 250 | 121.1111 |
| 500 | 260 |
| 1000 | 537.7778 |
Process temperatures are read in °C or °F; thermodynamic calculations use absolute K or °R.
A temperature difference is not the same as an absolute temperature: a 10 °C rise equals an 18 °F rise, but 10 °C does not equal 50 °F.
Worked example. A temperature of 302 °F is 150 °C.
Use °C = °F × 0.5555556 − 17.77778. Temperature scales are affine, so the conversion needs both a multiplier and an offset — unlike a simple unit factor.
1 °F equals -17.22222 °C. Note that a temperature difference converts differently from an absolute temperature.
Process temperatures are read in °C or °F; thermodynamic calculations use absolute K or °R.