How it works
Celsius sets water’s freezing point at 0° and boiling point at 100°; Fahrenheit sets them at 32° and 212°. That is 180 Fahrenheit degrees for every 100 Celsius degrees — a ratio of 9/5 — plus a 32-degree offset. Because of the offset, temperature cannot be converted with a single multiplier like other units.
The formula
°F = °C × 9 ÷ 5 + 32 °C = (°F − 32) × 5 ÷ 9Worked example. Body temperature 37 °C = 37 × 9 ÷ 5 + 32 = 98.6 °F. A 45 °C summer day in the Gulf is 113 °F. An oven at 350 °F is (350 − 32) × 5 ÷ 9 = 176.7 °C, usually written as 180 °C in recipes.
Quick reference table
| Celsius | Fahrenheit | Fahrenheit | Celsius |
|---|---|---|---|
| -40 °C | -40 °F | -40 °F | -40 °C |
| -10 °C | 14 °F | -10 °F | -23.3333 °C |
| 0 °C | 32 °F | 0 °F | -17.7778 °C |
| 10 °C | 50 °F | 10 °F | -12.2222 °C |
| 20 °C | 68 °F | 20 °F | -6.6667 °C |
| 25 °C | 77 °F | 25 °F | -3.8889 °C |
| 30 °C | 86 °F | 30 °F | -1.1111 °C |
| 37 °C | 98.6 °F | 37 °F | 2.7778 °C |
| 40 °C | 104 °F | 40 °F | 4.4444 °C |
| 45 °C | 113 °F | 45 °F | 7.2222 °C |
| 100 °C | 212 °F | 100 °F | 37.7778 °C |
| 180 °C | 356 °F | 180 °F | 82.2222 °C |
Useful reference points
- −40 °C = −40 °F — the only temperature that is the same on both scales.
- 0 °C = 32 °F (water freezes) and 100 °C = 212 °F (water boils at sea level).
- A fever is usually 38 °C (100.4 °F) or above.
Quick estimate: double the Celsius and add 30 (25 °C → 80 °F; exact 77 °F). For Kelvin, used in science, add 273.15 to Celsius — the unit converter includes it.
Converting recipe volumes too? Try the mL to oz converter.