Celsius to Kelvin Converter
To convert degrees Celsius to kelvin, add 273.15. Zero degrees Celsius is 273.15 K.
How to Convert Celsius to Kelvin
To convert degrees Celsius to kelvin, add 273.15.
For example: 25 °C + 273.15 = 298.15 K.
Where This Comes Up
Physics, chemistry and engineering calculations need an absolute scale, because ratios of temperature only make sense when zero means zero energy. Celsius readings from a thermometer have to be shifted onto that scale first.
Room temperature of 20 °C is 293.15 K, the value gas-law calculations use.
What People Get Wrong
Kelvin takes no degree sign and no "degrees": it is 300 K, not 300 °K. The unit is also written lowercase when spelled out, even though its symbol is a capital K.
Celsius to Kelvin Conversion Table
| Degrees Celsius (°C) | Kelvin (K) |
|---|---|
| -273.15 | 0 |
| -200 | 73.15 |
| -100 | 173.15 |
| -50 | 223.15 |
| -40 | 233.15 |
| -20 | 253.15 |
| -10 | 263.15 |
| 0 | 273.15 |
| 10 | 283.15 |
| 20 | 293.15 |
| 25 | 298.15 |
| 37 | 310.15 |
| 50 | 323.15 |
| 100 | 373.15 |
| 200 | 473.15 |
| 500 | 773.15 |
| 1,000 | 1,273.15 |
About These Units
The degree Celsius
The Celsius scale puts the freezing point of water at 0 degrees and its boiling point at 100 degrees at sea level. It is the everyday temperature scale in nearly every country except the United States.
The kelvin
The kelvin is the SI base unit of temperature and starts at absolute zero, the point where thermal motion stops. A change of 1 kelvin is exactly the same size as a change of 1 degree Celsius, and kelvin is written without a degree sign.
Definitions follow The SI Brochure, BIPM. See how we calculate for the exact values and rounding rules.
Frequently Asked Questions
Is a change of 1 °C the same as 1 K?
Yes, exactly. The two scales have the same degree size, so only the zero point differs. That makes temperature differences identical in both.
What is absolute zero in Celsius?
Absolute zero is 0 K, which is -273.15 °C. Nothing can be colder.
Why 273.15 and not 273?
The SI definition fixed the triple point of water at 273.16 K and 0.01 °C, which puts the Celsius zero at exactly 273.15 K.
What is body temperature in kelvin?
Normal body temperature of 37 °C is 310.15 K.