Celsius to Fahrenheit: Formula & Examples

One formula handles every Celsius-to-Fahrenheit conversion you'll ever need. Memorize it once, use it forever.

The formula

°F = (°C × 9/5) + 32. Multiply the Celsius temperature by 9, divide by 5, then add 32. That's the whole thing.

Worked example: 20°C

20 × 9 = 180; 180 ÷ 5 = 36; 36 + 32 = 68°F — room temperature. Another: 100°C → 100 × 9 = 900; ÷ 5 = 180; + 32 = 212°F — water's boiling point.

The quick estimation trick

Double the Celsius and add 30. 20°C → ~70°F (actual 68). It's within a few degrees — fine for weather, not for ovens or labs.

Common conversions to memorize

0°C = 32°F (freezing), 10°C = 50°F, 20°C = 68°F, 30°C = 86°F, 37°C = 98.6°F (body temp), 100°C = 212°F (boiling).

Going the other way

°C = (°F − 32) × 5/9. So 68°F → (68 − 32) = 36; 36 × 5 = 180; ÷ 9 = 20°C.

Skip the math

Our free Celsius to Fahrenheit converter gives the exact answer instantly — with the formula and FAQs on the page.