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How to Convert Celsius to Kelvin
Add 273.15 to the Celsius temperature. The Kelvin scale starts at absolute zero (-273.15 degrees C), so K = C + 273.15.
Celsius to Kelvin Conversion Table
| Celsius | Kelvin |
|---|---|
| -273.15 | 0 |
| -100 | 173.15 |
| 0 | 273.15 |
| 20 | 293.15 |
| 25 | 298.15 |
| 37 | 310.15 |
| 100 | 373.15 |
Common Use Cases
Physicists and chemists use the Kelvin scale for thermodynamic calculations because it begins at absolute zero, making it essential for equations involving the ideal gas law (PV = nRT), entropy, and Boltzmann statistics. A lab temperature of 25 degrees Celsius is 298.15 K, which is the standard reference temperature for reporting reaction enthalpies and equilibrium constants.
Astronomers report stellar surface temperatures, cosmic microwave background radiation, and planetary atmospheres in Kelvin. The Sun's surface temperature of about 5,778 K (5,505 degrees C) and the cosmic background temperature of 2.725 K are always expressed in Kelvin in astrophysical literature, making Celsius-to-Kelvin conversion fundamental for anyone studying space science.
Cryogenics engineers working with liquid nitrogen (-196 degrees C, or 77.15 K) and liquid helium (-269 degrees C, or 4.15 K) use Kelvin exclusively in technical specifications because the absence of negative numbers simplifies calculations for heat transfer, boil-off rates, and pressure-temperature phase diagrams in cryogenic system design.