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Celsius to Kelvin Converter

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Convert Celsius to Kelvin using the simple offset formula K = C + 273.15. The Celsius and Kelvin steps are equal in size, so a 10 °C temperature change is exactly a 10 K change. Useful for chemistry and physics problems where ideal-gas, Stefan–Boltzmann, Boltzmann distribution and other equations require absolute Kelvin input. Browser-local.

Decimal places:

From (Metric, Celsius)

Celsius (°C)

To (Metric, Kelvin)

Kelvin (K)

Celsius (°C) → Kelvin (K)

Quick reference table

Celsius (°C)	Kelvin (K)
-40 °C	233.15 K
-20 °C	253.15 K
0 °C	273.15 K
10 °C	283.15 K
20 °C	293.15 K
25 °C	298.15 K
37 °C	310.15 K
40 °C	313.15 K
60 °C	333.15 K
100 °C	373.15 K

Glossary

Celsius (°C)

Celsius is the metric temperature scale where the freezing point of water at standard atmospheric pressure is defined as 0 °C and the boiling point as 100 °C. Introduced by Anders Celsius in 1742 (originally with the scale inverted), it is now the everyday unit in nearly every country, in scientific notation alongside Kelvin, and the dominant unit for weather forecasts outside the US.

Kelvin (K)

Kelvin is the SI base unit of thermodynamic temperature. The scale starts at absolute zero (0 K = −273.15 °C) — the lowest temperature physically possible, where particle motion stops. One Kelvin step equals one Celsius step, so 0 °C = 273.15 K and 100 °C = 373.15 K. Used in physics, chemistry and engineering wherever absolute temperatures matter.

Metric / SI temperature

In the metric system, temperature is reported in degrees Celsius (everyday) or Kelvin (scientific). The two scales share the same step size — one Kelvin equals one degree Celsius — and differ only by the constant 273.15: T(K) = T(°C) + 273.15. The Kelvin scale starts at absolute zero, while Celsius is anchored to the freezing point of water at standard pressure.

Imperial / US Customary temperature

In the United States, everyday temperature is reported in degrees Fahrenheit, where water freezes at 32 °F and boils at 212 °F. The Rankine scale (absolute, anchored at 0 °R = absolute zero with the Fahrenheit step) is occasionally used in US thermodynamics and aerospace engineering. The conversion between Celsius and Fahrenheit uses the affine formula F = C × 9/5 + 32.

Related tools

Kelvin to Celsius

Convert K to °C — formula C = K − 273.15

Celsius to Fahrenheit

Convert °C to °F — formula F = C × 9/5 + 32

Fahrenheit to Kelvin

Convert °F to K — formula K = (F − 32) × 5/9 + 273.15

Temperature Converter

Convert temperatures between Celsius, Fahrenheit, Kelvin and Rankine