How to Convert Celsius to Fahrenheit

Almost the entire world measures temperature using the Celsius scale (°C), established by Swedish astronomer Anders Celsius. However, the United States, Liberia, and a handful of Caribbean territories continue to use the Fahrenheit scale (°F). If you travel abroad, read international recipes, or follow global weather forecasts, knowing how to convert between the two scales is a handy skill.

The Exact Conversion Formula

Because the Fahrenheit scale places the freezing point of water at 32° and boiling at 212° (a 180-degree spread), whereas Celsius uses 0° and 100° (a 100-degree spread), the ratio between the scales is 180/100, or 9/5 (1.8).

°F = (°C × 9/5) + 32
or
°F = (°C × 1.8) + 32

Step-by-Step Calculation

Convert 20°C (a pleasant room temperature) to Fahrenheit:

1. Multiply 20 by 1.8: 20 × 1.8 = 36.
2. Add 32: 36 + 32 = 68°F.

20°C is equal to 68°F.

A Handy Mental Math Shortcut

If you don't have a calculator handy and need a quick temperature estimate for the weather:

Quick Estimate: Double the Celsius temperature and add 30.

For 20°C: Double it (40), add 30 = 70°F (very close to the exact 68°F!).

Common Reference Benchmarks

• 0°C = 32°F: Water freezes.
• 10°C = 50°F: Brisk cool weather.
• 20°C = 68°F: Comfortable indoor room temperature.
• 30°C = 86°F: Warm summer day.
• 37°C = 98.6°F: Human body temperature.
• 100°C = 212°F: Water boils at sea level.

For immediate, accurate conversions across any temperature, use our Celsius to Fahrenheit Converter.