Temperature
Celsius, Fahrenheit and Kelvin.
About Temperature
Convert a temperature between Celsius, Fahrenheit and Kelvin. Enter one value, including zero or a negative, and the other two scales are shown at once.
How to use
- Type a value and pick its scale. The default is 0 °C.
- The other two scales update as you type; each row has its own Copy button, and Copy on the panel copies the whole table.
- Results are rounded to eight decimal places and formatted for your locale.
Formulas
Unlike the other unit converters, temperature scales have different zero points, so the conversion is an offset as well as a scale:
| From | To Celsius |
|---|---|
| Fahrenheit | (°F − 32) × 5 / 9 |
| Kelvin | K − 273.15 |
Then °F = °C × 9 / 5 + 32 and K = °C + 273.15. Zero and negative values are accepted. The tool does not reject values below absolute zero (−273.15 °C, −459.67 °F), so a negative Kelvin result means the input was physically impossible.
Example
100 °C → 212 °F · 373.15 K
-40 °C → -40 °F · 233.15 K
Privacy
Runs in the browser. No request is made, and nothing is stored.
Frequently asked questions
- How do I convert Celsius to Fahrenheit?
- Multiply by 9/5 (1.8) and add 32. So 20 °C is 68 °F, 37 °C (body temperature) is 98.6 °F, and 100 °C is 212 °F.
- At what temperature are Celsius and Fahrenheit equal?
- At −40 degrees. Setting C = C × 1.8 + 32 gives C = −40, the only point where the two scales read the same.
- What is 0 Kelvin in Celsius?
- −273.15 °C, which is absolute zero, the lowest possible temperature. Kelvin has the same step size as Celsius but no degree symbol and no negative values.
- Why is there no degree sign for Kelvin?
- Because the kelvin is an absolute SI unit, like the metre, rather than a scale measured from an arbitrary zero. Since 1967 the correct form is "300 K", not "300 °K".