Celsius to kelvin converter
Convertersconversion pair
Convert celsius to kelvin instantly: K = °C + 273.15. Science, weather and engineering, with the exact formula and a copy button.
273.15 to the offset — where Celsius stops pretending to be relative.
work surface
Math, not advice — results are indicative. Read the disclaimer.
pro tips
Add 273.15: 20 °C is 293.15 K. Same size degrees, different floor.
0 °C is 273.15 K — freezing, in absolute terms.
Kelvin has no degree symbol and no negatives; if your answer is negative, you've subtracted instead of added.
what it does
Celsius to kelvin is the friendliest conversion in temperature: add 273.15 and you're done. Kelvin uses the same step size as Celsius, so there's no multiplication — just an honest offset from absolute zero.
It shows up in physics and chemistry, where temperature has to be absolute for the equations to work, in astronomy where the sky is measured in kelvin, in engineering specs where −273.15 °C is the floor and nothing goes below, and in any science class where someone forgets the offset and gets a plausible-looking wrong answer.
The shortcut: 0 °C is 273.15 K, 100 °C is 373.15 K, and −273.15 °C is absolute zero, where molecules stop and the conversation ends. Kelvin never goes negative, which is the whole point — it starts where cold stops.
Type any celsius value and the widget answers in kelvin instantly, with the math in the hint. Click to copy, and swap when a kelvin figure has to be read back in celsius.
quick answers
How do I convert celsius to kelvin?
Add 273.15. That's it — no 1.8, no 32.
Is kelvin a degree?
No. It's just "kelvin", written 300 K, not 300 °K.
Why does science use kelvin?
Because absolute temperature makes the equations work, and 0 K is a real floor, not a convention.