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Convert Celsius to Kelvin

Celsius to Kelvin conversion table

Celsius (°C)Kelvin (K)
1 °C274.15 K
2 °C275.15 K
5 °C278.15 K
10 °C283.15 K
25 °C298.15 K
50 °C323.15 K
100 °C373.15 K
200 °C473.15 K
500 °C773.15 K
1000 °C1273.15 K

How to convert celsius to kelvin

Kelvin is the SI base unit for thermodynamic temperature, used in science and engineering. Unlike Celsius and Fahrenheit, Kelvin has no negative values — absolute zero is 0 K (−273.15°C). The size of one kelvin equals one degree Celsius; only the starting point differs.

Formula: K = °C + 273.15. Example: 0°C = 273.15 K (water freezing). 25°C = 298.15 K (room temperature). −40°C = 233.15 K.

Chemistry, physics, and gas law calculations (PV = nRT) require Kelvin. You cannot use Celsius in these equations because they depend on absolute temperature, not relative degrees.

Remember: never say 'degrees Kelvin' — just 'kelvin' or 'K'. The offset 273.15 is exact by definition. 100°C = 373.15 K (water boiling).

Related conversions

Kelvin to Celsius

Frequently asked questions

Add 273.15 to the Celsius value. K = °C + 273.15.

About 20°C = 293.15 K, often rounded to 293 K in calculations.

Kelvin starts at absolute zero, where molecular motion ceases. Many physical laws (gas behavior, thermal radiation) require absolute temperature.