°F to °C — convert degrees Fahrenheit to degrees Celsius
Exact 1 × 0.55555556 − 17.777778 = -17.222222
1 degree Fahrenheit in other units
| Degrees Celsius | -17.222222 | °C |
|---|---|---|
| Kelvin | 255.927778 | K |
| Degrees Rankine | 460.67 | °R |
°F to °C at a glance
| Degrees Fahrenheit | Degrees Celsius |
|---|---|
| 1 °F | -17.222222 °C |
| 2 °F | -16.666667 °C |
| 3 °F | -16.111111 °C |
| 5 °F | -15 °C |
| 10 °F | -12.222222 °C |
| 20 °F | -6.666667 °C |
| 25 °F | -3.888889 °C |
| 50 °F | 10 °C |
| 100 °F | 37.777778 °C |
| 250 °F | 121.111111 °C |
| 500 °F | 260 °C |
| 1,000 °F | 537.777778 °C |
How to convert degrees Fahrenheit to degrees Celsius
Multiply by -17.222222 — one degree Fahrenheit is -17.222222 degrees Celsius. That factor is exact: it comes from the definition of the units rather than from a measurement, so it will not change and does not need rounding.
Working 1 × 0.55555556 − 17.777778 = -17.222222
In words: about minus seventeen degrees Celsius.
What these units are
The degree Fahrenheit and the degree Celsius are covered in the temperature unit guide, along with every other unit on this page.
Questions
How many degrees Celsius are in a degree Fahrenheit?
One degree Fahrenheit is -17.222222 degrees Celsius. This figure is exact — it comes from the definition of the unit, not a measurement.
What is 1 degree Fahrenheit in degrees Celsius?
1 degree Fahrenheit is -17.222222 degrees Celsius. The working is 1 × 0.55555556 − 17.777778 = -17.222222.
Why can't I just multiply to convert Celsius to Fahrenheit?
Because the two scales do not start in the same place. Zero Celsius is 32 Fahrenheit, so you have to shift as well as scale: multiply by 9/5, then add 32. Multiplying alone is right only for a temperature difference, never a temperature.
Where do the two scales meet?
At −40. Minus forty Celsius and minus forty Fahrenheit are the same temperature, which is the one value you can quote in either scale without converting.
Is it 'degrees Kelvin'?
No. Kelvin is written without the degree sign and without the word degree — 300 K, read as three hundred kelvin. It is an absolute scale, so there is no offset to name.
What is Rankine for?
Rankine is Fahrenheit's absolute scale: same size step, but starting at absolute zero instead of the Fahrenheit zero. It still turns up in US thermodynamics and aerospace work.