Celsius to Fahrenheit: Formula and Conversion Chart (°C to °F)
To convert Celsius to Fahrenheit, multiply by 9/5 (1.8) and add 32. To convert Fahrenheit to Celsius, subtract 32, then multiply by 5/9. So 20°C = 68°F, and 100°F ≈ 37.8°C. The two scales cross at one point only: −40°C equals exactly −40°F. Everything below follows from these two formulas.
What is the Celsius to Fahrenheit formula?
°F = (°C × 9/5) + 32
Example: 25°C → (25 × 1.8) + 32 = 45 + 32 = 77°F. For a fast estimate, double the Celsius value and add 30 (25 → 50 + 30 = 80, close enough for weather). For exact results, use the Celsius to Fahrenheit converter.
What is the Fahrenheit to Celsius formula?
°C = (°F − 32) × 5/9
Example: 98.6°F → (98.6 − 32) × 5/9 = 66.6 × 0.5556 = 37°C. The reverse shortcut: subtract 30 and halve (80 → 50/2 = 25, close to the exact 26.7°C). For precise values, use the Fahrenheit to Celsius converter.
Celsius to Fahrenheit conversion chart
| Celsius (°C) | Fahrenheit (°F) | Reference |
|---|---|---|
| −40°C | −40°F | Scales meet |
| 0°C | 32°F | Water freezes |
| 20°C | 68°F | Room temperature |
| 37°C | 98.6°F | Body temperature |
| 40°C | 104°F | High fever / hot day |
| 100°C | 212°F | Water boils |
Why do some countries use Fahrenheit and others Celsius?
Celsius is part of the metric system and is used almost everywhere in the world, including for science. Fahrenheit remains the everyday scale in the United States and a few territories. That's why you most often need to convert when checking US weather forecasts, following American cooking and oven recipes, or reading medical temperatures. Because both are linear scales, the formulas above always hold.
Helpful tools
- Celsius to Fahrenheit Converter
- Fahrenheit to Celsius Converter
- Temperature Converter — includes Kelvin and more.