Fahrenheit to Kelvin

Degrees Fahrenheit and kelvins

The Fahrenheit scale puts water's freezing point at 32 °F and boiling at 212 °F; one Fahrenheit degree is 5/9 of a Celsius degree. The United States and a few Caribbean countries use Fahrenheit for weather, ovens and body temperature.

The kelvin is the SI base unit of thermodynamic temperature, starting at absolute zero; since 2019 it is defined by fixing the Boltzmann constant. Science and engineering use kelvins, as do color temperatures of light bulbs and screens (2700 K warm, 6500 K daylight).

Worked example

Convert 72 °F with K = (°F − 32) × 5/9 + 273.15: the result is 295.3722222 K. Likewise 50 °F = 283.15 K.

Estimating in your head

Go through Celsius: subtract 32, multiply by 5/9, then add 273.15. 72 °F → 22.2 °C → 295.4 K.

Going the other way

To convert kelvins to degrees Fahrenheit, type in the right-hand box; the page solves the same formula backwards. The swap button between the boxes opens the reverse page.

K = (°F − 32) × 5/9 + 273.15

Temperature scales have different zero points as well as different degree sizes, so the conversion scales and shifts; there is no single factor. The page converts through kelvin using the exact definitions in NIST SP 811. Results drop binary floating-point noise beyond 15 significant digits and display at the precision you choose (6 significant figures by default). Copy result copies the full value.