Fahrenheit to Celsius (°F to °C): Chart, Formula, & History
Need to convert Fahrenheit to Celsius? This guide has the formula, a conversion chart, and a short history of both scales.
Temperature conversions are a small but surprisingly common skill — from cooking recipes to chemistry class to SAT science-adjacent questions. Here's everything you need to know, plus a handy chart you can memorize.
The formula
To convert Fahrenheit to Celsius:
°C = (°F − 32) × 5 / 9
To convert Celsius to Fahrenheit (just in case):
°F = (°C × 9 / 5) + 32
Quick mental math trick
If you're approximating: subtract 30 and halve. Close enough for weather.
- 70 °F → (70 − 30) / 2 = 20 °C (actual: 21.1 °C)
- 90 °F → (90 − 30) / 2 = 30 °C (actual: 32.2 °C)
Conversion chart
| Fahrenheit | Celsius | | --- | --- | | −40 °F | −40 °C | | 0 °F | −17.8 °C | | 32 °F | 0 °C (water freezes) | | 50 °F | 10 °C | | 68 °F | 20 °C (room temp) | | 98.6 °F | 37 °C (body temp) | | 212 °F | 100 °C (water boils) |
A little history
- Fahrenheit was proposed in 1724 by Daniel Gabriel Fahrenheit. His 0 °F was the freezing point of a brine solution of ammonium chloride.
- Celsius was proposed in 1742 by Anders Celsius. He originally set 0 °C at boiling and 100 °C at freezing — it was later flipped.
Tip for tests
Memorize the −40 crossover: it's the one temperature where Fahrenheit and Celsius agree. Makes for a nice sanity check if you ever doubt your arithmetic.
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