Kelvin to Celsius
Subtract 273.15 — an exact figure rather than a rounded one, because the two scales are defined to share a degree size and differ only by a shift.
Subtract 273.15 exactly. The two scales were defined to share a degree size, so this is a shift and not a scaling — a rise of one kelvin is a rise of one degree Celsius, always.
With temperature 72, temperature converter comes to -201.15 — converted value. It is reached in 4 steps, the last of which is -201.15 * 1 + -330.07 * 0 + 72 * 0, and each one is printed on the page with its numbers filled in. The formula is the one published by NIST, not an approximation fitted to it.
Formula and sources checked · How we check
- In Celsius
72 * 0 + (72 - 32) * 5 / 9 * 0 + (72 - 273.15) * 1-201.15 °C- In Fahrenheit
-201.15 * 9 / 5 + 32-330.07 °F- In Kelvin
-201.15 + 273.1572 K- Converted value
-201.15 * 1 + -330.07 * 0 + 72 * 0-201.15
Why 273.15 rather than 273?
Because the kelvin was fixed from the triple point of water, which sits at 0.01°C, and the scale is anchored there. The fifteen hundredths decide a laboratory measurement and never a weather forecast, but carrying the exact figure costs nothing and rounding it is a choice you cannot undo later.
Can a kelvin figure be negative?
Not in the ordinary sense. Zero kelvin is absolute zero, the coldest state there is, and it sits at −273.15°C. If a conversion here hands back a negative kelvin figure, the Celsius value that went in was below absolute zero and is not a temperature at all.
The formula
- In Celsius
value * from_c + (value - 32) * 5 / 9 * from_f + (value - 273.15) * from_k - In Fahrenheit
celsius * 9 / 5 + 32 - In Kelvin
celsius + 273.15 - Converted value
celsius * to_c + fahrenheit * to_f + kelvin * to_k
Formula from NIST — SI units and temperature scales, BIPM — the kelvin and the International System of Units.
The same calculator, other cases
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