18 Celsius to kelvin
291.15 K
18 °C = 291.15 K.
kelvin
291.15K
18 °C = 291.15 K
In short
How many kelvin is 18 Celsius?
18 °C = 291.15 K. 1 Celsius = 1.000000 kelvin, then + 273.15, so the working is 18 × 1.000000 + 273.1500 = 291.15.
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 18 × 1.000000 + 273.1500 = 291.15
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 | 291 | −0.15000 |
| 1 decimal | 291.1 | −0.05000 |
| 2 decimals | 291.15 | exact |
Round trip: take 291.15 K back the other way and you land on 18.0000 °C — a drift of 0.0000 °C. That gap is the rounding, not the conversion.
What 18 °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 18 Celsius in kelvin?
18 Celsius is 291.15 kelvin. 1 Celsius = 1.000000 kelvin, then + 273.15, so the working is 18 × 1.000000 + 273.1500 = 291.15.
How accurate is 291.15 K?
Rounding to 291.15 K and converting straight back gives 18.0000 °C, a drift of 0.0000 °C from the 18 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.
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