Converting temperature
Temperature scales don't share a zero, so you can't convert with a single multiplier. Celsius to Fahrenheit multiplies by 9/5 and adds 32; Celsius to Kelvin adds 273.15. This tool converts your input to Celsius first, then out to the target scale, which handles every pair correctly.
The scales at a glance
Water freezes at 0 °C, 32 °F and 273.15 K, and boils at 100 °C, 212 °F and 373.15 K. Kelvin starts at absolute zero and is used in science; Fahrenheit is standard in the US; Celsius is used almost everywhere else.
Quick sanity checks
Body temperature is about 37 °C or 98.6 °F. A warm day of 30 °C is 86 °F. If a conversion looks far off, check you haven't swapped the from and to scales.
Frequently asked questions
What is 100°C in Fahrenheit?
212 °F — the boiling point of water at sea level.
Why add 273.15 for Kelvin?
Kelvin measures from absolute zero, which sits 273.15 degrees below the freezing point of water.
How do I convert Celsius to Fahrenheit?
°F = °C × 9/5 + 32. So 20 °C is 68 °F and 37 °C is 98.6 °F.
How do I convert Fahrenheit to Celsius?
°C = (°F − 32) × 5/9. So 100 °F is about 37.8 °C.
What is absolute zero in Kelvin?
0 K equals −273.15 °C. To go from °C to Kelvin, add 273.15.