Celsius to Kelvin Converter

About °C → K

Kelvin is the SI absolute temperature scale with zero at absolute zero. Celsius shares the same step size but starts at water's freeze point offset.

Add 273.15 to Celsius to obtain Kelvin for physics equations.

Celsius in, Kelvin out—not Kelvin to Celsius (see k-to-c).

How to use this tool

Enter Celsius. Calculate to view Kelvin.

Formula & methodology

This celsius to kelvin converter applies the standard relationship below. Intermediate values are kept at full precision; only the displayed result is rounded.

K = C + 273.15

Tips for accurate results

• Kelvin never uses degree symbol in SI usage.
• 0 K is unattainable physically; 0 C is 273.15 K.
• Use k-to-c for inverse.
• Gas law calculations require Kelvin, not Celsius.

Frequently asked questions

Sources & references

The factors and formulas used by this tool follow these references:

• NIST Special Publication 811 — Guide for the Use of the International System of Units (SI)
• BIPM — The International System of Units (SI Brochure, 9th edition)

Last reviewed: September 2026. Found an error? Tell us and we will correct it.