Convert degrees Fahrenheit to degrees Celsius
Convert degrees Fahrenheit to degrees Celsius, with the formula and a quick reference table.
°C = (°F − 32) × 5/9
All temperature units
| Unit | Value | Symbol |
|---|---|---|
| -17.222222 | °C | |
| 1 | °F | |
| 255.92778 | K | |
| 460.67 | °R |
degrees Fahrenheit to degrees Celsius at a glance
| °F | °C |
|---|---|
| -40 | -40 |
| 0 | -17.7778 |
| 20 | -6.66667 |
| 32 | 0 |
| 50 | 10 |
| 68 | 20 |
| 98.6 | 37 |
| 100 | 37.7778 |
| 212 | 100 |
Other temperature conversions
How it works
Every unit in this dimension is defined as a ratio to one base unit — the kelvin. Converting is therefore two multiplications: into the base unit, then out of it.
°C = (°F − 32) × 5/9 Temperature is the exception. Its scales have different zero points as well as different step sizes, so the conversion is affine (multiply and shift) rather than a single ratio. That is why −40 °C and −40 °F are the same temperature: it is the one point where the two lines cross.
Rounding
Results are rounded to 8 significant figures, adjustable with the slider above. Exact factors are used internally, so chaining conversions does not accumulate error.
Sources
Conversion factors follow NIST Special Publication 811 (Guide for the Use of the International System of Units) and the BIPM SI Brochure, 9th edition. Every factor is checked by an automated round-trip test on each build.