The exact formula
°F = °C × 1.8 + 32. Multiply by 1.8 (or 9/5), then add 32. For example, 25 °C × 1.8 = 45, plus 32 is 77 °F.
Going the other way: °C = (°F − 32) ÷ 1.8. For example, (68 °F − 32) ÷ 1.8 = 20 °C.
A quick mental trick
Double the Celsius and add 30. 20 °C becomes 70 °F (exactly 68). It is within a few degrees for everyday weather, but drifts further off at oven and freezer temperatures. To go back, subtract 30 and halve.
Temperatures worth remembering
| Celsius | Fahrenheit |
| −40 °C | −40 °F (the two scales meet) |
| 0 °C | 32 °F (water freezes) |
| 20 °C | 68 °F (room temperature) |
| 37 °C | 98.6 °F (body temperature) |
| 100 °C | 212 °F (water boils at sea level) |
| 180 °C | 356 °F (a common oven setting, usually written 350 °F) |
Convert any value
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