Convert Fahrenheit to Kelvin

1. How to convert Fahrenheit to Kelvin

Fahrenheit and Kelvin do not share a zero point, so the conversion needs an offset as well as a ratio: K = (°F + 459.67) × 5/9. That is an affine conversion, not a proportional one.

Worked at the two values people ask for most: 1 °F = 255.92778 K and 72 °F = 295.37222 K. Going the other way, °F = (K × 9/5) − 459.67, so 1 K = -457.87 °F.

Results are given to eight significant figures. That is more precision than most jobs need — for a rough figure, treat 1 °F as about 255.92778 K and adjust — but rounding early and multiplying afterwards is how a small error becomes a visible one, so the full figure is what the converter carries.

2. Fahrenheit to Kelvin conversion table

Every row is the same factor applied — nothing in the table is a special case, and any value in between behaves the same way. Type your own figure into the converter above and the Formula tile shows the arithmetic being used, so the result is checkable rather than taken on trust.

3. What the two units are

• Fahrenheit (°F). Fahrenheit puts freezing at 32 and boiling at 212, so its degree is 5/9 the size of a Celsius one.
• Kelvin (K). Kelvin starts at absolute zero and uses the Celsius degree, so 0 K is −273.15 °C.

Both scales are converted through kelvin internally, which is why the arithmetic handles negative values correctly — an offset applied in the wrong order is the usual source of a wrong answer here.

Temperature is the one category that needs an offset as well as a factor, because the scales do not share a zero. That has a consequence people trip over constantly: you cannot convert a temperature difference the same way you convert a temperature. A room at 20 °C is 68 °F, but a rise of 20 °C is a rise of 36 °F. For an interval, apply the 9/5 ratio and drop the offset.

If the pair you actually want is not this one, the full unit converter runs every 4 temperature units off the same factor table, along with 11 other categories of measurement.