Temperature Converter
Convert Celsius, Fahrenheit, Kelvin, and Rankine — type in any field.
Temperature scale overview
| Scale | Water freezes | Water boils | Absolute zero |
|---|---|---|---|
| Celsius (°C) | 0 | 100 | −273.15 |
| Fahrenheit (°F) | 32 | 212 | −459.67 |
| Kelvin (K) | 273.15 | 373.15 | 0 |
| Rankine (°R) | 491.67 | 671.67 | 0 |
Frequently asked questions
How do I convert Celsius to Fahrenheit?
Multiply by 9/5 then add 32: °F = (°C × 9/5) + 32. To go the other way, subtract 32 then multiply by 5/9: °C = (°F − 32) × 5/9. A handy shortcut: 100°C = 212°F and 0°C = 32°F.
What is Kelvin used for?
Kelvin is the SI base unit of thermodynamic temperature, used in physics, chemistry, and engineering. Unlike Celsius and Fahrenheit, Kelvin starts at absolute zero (the coldest possible temperature), so there are no negative Kelvin values. It is essential in gas law calculations, astrophysics, and semiconductor physics.
What is the Rankine scale?
Rankine is an absolute temperature scale based on Fahrenheit — just as Kelvin is the absolute version of Celsius. 0°R = absolute zero, and the degree size matches Fahrenheit (1°R = 1°F difference). It is used in some US engineering contexts, particularly in thermodynamics and aerospace. Water freezes at 491.67°R and boils at 671.67°R.
