About the °c to k calculation
Converting celsius to kelvin is not a simple multiplication, because the two scales start from different zero points. One degree Celsius corresponds to 274.15 kelvin, but that ratio does not hold at other values — the formula below is what you actually need. The everyday temperature scale nearly everywhere, with 0 at the freezing point of water and 100 at its boiling point. The SI temperature unit. It starts at absolute zero, so it never goes negative and takes no degree symbol.
Formula
K = °C + 273.15Worked example
Converting 25 °C through the formula above gives 298.15 K.
Frequently asked questions
How many kelvin are in a degree Celsius?
One degree Celsius equals 274.15 kelvin. Because these are temperature scales with different zero points, this is not a ratio you can multiply by — you have to apply the full formula for any other value.
How do I convert kelvin back to celsius?
Reverse the formula: undo the addition first, then the multiplication. One kelvin works out as -272.15 celsius. Our Kelvin to Celsius page does it for you.
Is this conversion exact?
Yes. The Celsius, Fahrenheit and Kelvin scales are defined in terms of each other exactly, so the conversion carries no rounding error beyond what we display.
Where is each of these units used?
Celsius: the everyday temperature scale nearly everywhere, with 0 at the freezing point of water and 100 at its boiling point. Kelvin: the SI temperature unit. It starts at absolute zero, so it never goes negative and takes no degree symbol.
Sources
- NIST Special Publication 811 — Guide for the Use of the International System of Units