Celsius to Fahrenheit: The Formula Explained
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The formula
°F = (°C × 9/5) + 32
Reversed, to go from Fahrenheit back to Celsius: °C = (°F − 32) × 5/9
A quick mental-math shortcut
For a rough estimate without a calculator: double the Celsius value, subtract 10%, then add 32.
Example: 20°C × 2 = 40, minus 10% (4) = 36, plus 32 = 68°F — matching the exact formula.
Reference points worth memorizing
| Celsius | Fahrenheit | Reference |
|---|---|---|
| 0°C | 32°F | Water freezes |
| 37°C | 98.6°F | Body temperature |
| 100°C | 212°F | Water boils |
For exact conversions without doing the math yourself, use our Celsius to Fahrenheit converter.