Skip to content

Celsius to Kelvin

Convert Celsius (°C) to Kelvin (K). K = °C + 273.15. Runs locally in your browser.

=
Kelvin (K) 298.15

Celsius to Kelvin table

CelsiusKelvin
-40 °C233.15 K
0 °C273.15 K
10 °C283.15 K
20 °C293.15 K
25 °C298.15 K
30 °C303.15 K
37 °C310.15 K
50 °C323.15 K
100 °C373.15 K

Where this conversion shows up

This is the science-class conversion. Gas laws, thermodynamics and chemistry equations need absolute temperature — kelvin — because doubling the temperature only doubles the energy if your zero is true zero. Everyday Celsius readings must be shifted before they go into any formula.

Worked example

A lab at 25 °C: 25 + 273.15 = 298.15 K, the standard temperature in chemistry. Water boils at 100 °C = 373.15 K, and absolute zero is 0 K = −273.15 °C.

Rounding and precision

The shift is exact — just addition, no scaling — so kelvin values carry the same precision as the Celsius reading. Note the style rule: kelvin takes no degree sign (298 K, not 298 °K), and the unit is lowercase when written out.

FAQ

What is the formula to convert Celsius to Kelvin?

K = °C + 273.15. For example, 25 °C = 298.15 K.

Is Celsius to Kelvin done in my browser?

Yes — the conversion runs locally; nothing is uploaded.

Why add exactly 273.15?

Absolute zero — where particles have minimal thermal energy — sits at −273.15 °C. The kelvin scale starts there and uses the same step size as Celsius, so converting is a pure offset.

Can a temperature in kelvin be negative?

No. Zero kelvin is absolute zero, the floor of the scale, so ordinary temperatures are always positive. (Negative-kelvin states in physics papers are exotic population inversions, not "colder than zero".)

Related conversions