How to Convert Celsius to Fahrenheit (Formula + Free Converter)

If you've ever traveled between countries that use different temperature scales, you know the awkward pause when someone says 'it's 32 outside.' Is that freezing or beach weather? Here's how to convert quickly.

The exact formula

Fahrenheit = (Celsius × 9 ÷ 5) + 32. So 20°C × 9 ÷ 5 = 36, plus 32 = 68°F.

The mental-math shortcut

Double the Celsius, add 30. It is not exact, but it is within a couple of degrees for everyday weather: 20°C → 40 + 30 = 70°F (real answer: 68°F).

Reference points worth memorizing

• 0°C = 32°F (water freezes)
• 10°C = 50°F (cool jacket weather)
• 20°C = 68°F (room temperature)
• 30°C = 86°F (hot summer day)
• 37°C = 98.6°F (body temperature)
• 100°C = 212°F (water boils)

Convert any value instantly

Skip the math and use our Temperature Converter. It handles Celsius, Fahrenheit, and Kelvin in both directions. Need other units? Try Length Converter and Weight Converter.