21 Celsius to kelvin
294.15 K
21 °C = 294.15 K.
kelvin
294.15K
21 °C = 294.15 K
In short
How many kelvin is 21 Celsius?
21 °C = 294.15 K. 1 Celsius = 1.000000 kelvin, then + 273.15, so the working is 21 × 1.000000 + 273.1500 = 294.15.
The working
The factor below is an exact definition rather than a measurement, so nothing is approximated in the arithmetic. The only rounding on this page happens where a number is displayed.
1 Celsius = 1.000000 kelvin, then + 273.15 21 × 1.000000 + 273.1500 = 294.15
How much precision do you need?
Each row is the same answer cut at a different number of decimals, with what that choice costs you. Pick the shortest row whose error is smaller than whatever you are measuring with.
| Rounded to | Answer (K) | Off by |
|---|---|---|
| Whole number | 294 | −0.15000 |
| 1 decimal | 294.1 | −0.05000 |
| 2 decimals | 294.15 | exact |
Round trip: take 294.15 K back the other way and you land on 21.0000 °C — a drift of 0.0000 °C. That gap is the rounding, not the conversion.
What 21 °C looks like
20 °C
Room temperature by convention, 293.15 kelvin, and the reference temperature a great many physical constants are quoted at.
Frequently asked questions
What is 21 Celsius in kelvin?
21 Celsius is 294.15 kelvin. 1 Celsius = 1.000000 kelvin, then + 273.15, so the working is 21 × 1.000000 + 273.1500 = 294.15.
How accurate is 294.15 K?
Rounding to 294.15 K and converting straight back gives 21.0000 °C, a drift of 0.0000 °C from the 21 you started with. The factor itself is exact; every bit of that difference comes from the rounding, not the conversion.
Nearby values
Any value at all
Celsius to Kelvin Converter
Convert Celsius to kelvin — gas-law problems, absolute temperature, and lab work.
Open the celsius to kelvin converter →