Temperature Converter: Fahrenheit, Celsius & Kelvin
Convert between Fahrenheit, Celsius, and Kelvin.
Conversion Formulas
| From | To | Formula | Example |
|---|---|---|---|
| °F | °C | (°F − 32) ÷ 1.8 | 86°F = 30°C |
| °C | °F | (°C × 1.8) + 32 | 20°C = 68°F |
| °C | K | °C + 273.15 | 25°C = 298.15 K |
| K | °C | K − 273.15 | 300 K = 26.85°C |
| °F | K | ((°F − 32) ÷ 1.8) + 273.15 | 98.6°F = 310.15 K |
| K | °F | ((K − 273.15) × 1.8) + 32 | 300 K = 80.33°F |
Mental Math Shortcuts
For quick Fahrenheit/Celsius estimates:
- °F to °C: Subtract 30, then divide by 2 (86°F → 56 ÷ 2 ≈ 28°C, actual: 30°C)
- °C to °F: Double it, then add 30 (20°C → 40 + 30 ≈ 70°F, actual: 68°F)
These approximations are close enough for daily use. The error is usually just 1-2 degrees.
About the Scales
Celsius (°C) is the global standard for weather and everyday temperature. Water freezes at 0°C and boils at 100°C at sea level. Most of the world uses Celsius exclusively.
Fahrenheit (°F) is primarily American. Water freezes at 32°F and boils at 212°F. The scale gives finer gradations for everyday temperatures – the difference between 70°F and 71°F is smaller than between 21°C and 22°C.
Kelvin (K) starts at absolute zero (the coldest possible temperature) and uses the same degree size as Celsius. Scientists use it because there are no negative numbers and it relates directly to molecular energy. Note: We say “300 Kelvin,” not “300 degrees Kelvin” – no degree symbol.
Water’s freezing and boiling points: 0°C = 32°F = 273.15 K and 100°C = 212°F = 373.15 K