Temperature Converter
Convert temperatures between Celsius, Fahrenheit and Kelvin for weather, cooking, science and travel. Unlike most units, temperature scales have different zero points, so converting means applying a formula rather than multiplying by one factor.
degrees Fahrenheit
Popular temperature conversions
Units in this converter
| Unit | Symbol | Water freezes at |
|---|---|---|
| Celsius | °C | 0 °C |
| Fahrenheit | °F | 32 °F |
| Kelvin | K | 273.15 K |
Temperature formulas
Celsius to Fahrenheit: °F = °C × 9/5 + 32. Fahrenheit to Celsius: °C = (°F − 32) × 5/9. Celsius to Kelvin: K = °C + 273.15.
Temperatures below absolute zero (−273.15 °C, −459.67 °F or 0 K) are physically impossible, so the converter rejects them.
About the units
- Celsius (°C)
- On the Celsius scale water freezes at 0 °C and boils at about 100 °C at sea-level pressure. Today it is formally defined from the kelvin (°C = K − 273.15). It is the scale used for weather and cooking in almost every country.
- Fahrenheit (°F)
- On the Fahrenheit scale water freezes at 32 °F and boils at 212 °F, so one Fahrenheit degree is 5/9 of a Celsius degree. It is the everyday scale in the United States for weather, ovens and body temperature.
- Kelvin (K)
- The kelvin is the SI base unit of temperature. Its scale starts at absolute zero, so there are no negative kelvin values, and a change of 1 K equals a change of 1 °C. It is written without a degree sign.
Frequently asked questions
At what temperature are Celsius and Fahrenheit equal?
At −40 degrees. −40 °C is exactly −40 °F.
Why can’t Kelvin be negative?
The Kelvin scale starts at absolute zero, the lowest temperature possible. Nothing can be colder, so there are no negative kelvin values.