Temperature Converter
Celsius, Fahrenheit, and Kelvin — enter one and the other two update on the spot.
How it works
Temperature isn't a simple multiply-by-a-factor conversion, because the scales don't share a zero. Celsius and Fahrenheit are offset, and Kelvin starts at absolute zero, so each pair needs its own little formula.
The math the tool uses: Fahrenheit is Celsius times 9/5 plus 32; Kelvin is Celsius plus 273.15. To go backwards it just runs those in reverse. Water freezes at 0 °C / 32 °F / 273.15 K and boils at 100 °C / 212 °F.
A handy mental shortcut: double the Celsius figure and add 30 for a rough Fahrenheit estimate. It's off by a few degrees, but close enough to know whether to grab a jacket.
Frequently asked questions
How do I convert Celsius to Fahrenheit?
Multiply by 9/5 and add 32. So 20 °C is (20 × 1.8) + 32 = 68 °F. Enter Celsius above and read the Fahrenheit box.
What is 98.6 °F in Celsius?
37 °C — normal human body temperature. Subtract 32 and multiply by 5/9 to convert Fahrenheit to Celsius yourself.
Why does Kelvin not use a degree sign?
Kelvin is an absolute scale starting at absolute zero, so its values are just 'kelvin', not 'degrees kelvin'. Zero kelvin is -273.15 °C, the coldest anything can theoretically get.