Celsius to Kelvin Converter

Celsius to Kelvin Converter

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Formula: K = °C + 273.15

How to convert Celsius to Kelvin

To convert Celsius to Kelvin, add 273.15. Formula: K = °C + 273.15. For example, 100°C + 273.15 = 373.15 K. Going the other way, subtract 273.15 from Kelvin to get Celsius.

The Kelvin scale starts at absolute zero — the coldest possible temperature — which is −273.15°C. This means 0°C = 273.15 K and 0 K = −273.15°C.

Kelvin is the SI unit of temperature used in science and physics. Unlike Celsius and Fahrenheit, Kelvin has no degree symbol — temperatures are written as “373 K” not “373°K”. Kelvin is essential in thermodynamics, chemistry, and astrophysics.

Celsius to Kelvin conversion table

Celsius (°C) Kelvin (K) Description
−273.15°C0 KAbsolute zero
−200°C73.15 KLiquid nitrogen range
−100°C173.15 KExtreme cold
−40°C233.15 K−40°F (scales equal)
0°C273.15 KFreezing point of water
20°C293.15 KRoom temperature
37°C310.15 KBody temperature
100°C373.15 KBoiling point of water
1000°C1273.15 KLava temperature

Frequently asked questions

What is 0°C in Kelvin?
0°C = 273.15 K. This is the freezing point of water. The Kelvin scale starts 273.15 degrees below the freezing point of water.
What is 100°C in Kelvin?
100°C = 373.15 K. This is the boiling point of water at standard atmospheric pressure.
What is absolute zero in Celsius?
Absolute zero = 0 K = −273.15°C. This is the coldest possible temperature — the point at which all molecular motion stops.
Why does Kelvin have no degree symbol?
The kelvin is an absolute scale with a defined zero point, so it is treated as a unit like meters or kilograms rather than a relative scale like Celsius or Fahrenheit. Temperatures are written as “300 K” not “300°K”.
What is room temperature in Kelvin?
Room temperature (20°C) = 293.15 K. In chemistry, standard temperature is defined as 25°C = 298.15 K.