Fahrenheit to Kelvin Converter

Subtract 32 from the Fahrenheit value, multiply by 5/9 to get Celsius, then add 273.15. The full formula is K = (F - 32) x 5/9 + 273.15. For example, 68 F becomes (68 - 32) x 5/9 = 20 C, and 20 + 273.15 = 293.15 K.

Subtract 273.15 from the Kelvin value to get Celsius, multiply by 9/5, then add 32. The formula is F = (K - 273.15) x 9/5 + 32. For example, 300 K is 26.85 C, and 26.85 x 9/5 + 32 = 80.33 F.

Absolute zero is the lowest possible temperature, where molecular motion stops. It is 0 K, which equals exactly -459.67 F and -273.15 C. This converter rejects any Fahrenheit value below -459.67 or any negative Kelvin value, since temperatures colder than absolute zero are not physically possible.

Kelvin and Celsius use the same degree size, so a change of 1 K equals a change of 1 C. The only difference is where each scale starts. Kelvin places its zero at absolute zero, while Celsius places its zero at the freezing point of water, which sits 273.15 degrees higher. That fixed gap is the 273.15 you add or subtract.

Celsius is the bridge between the two scales, since Kelvin is just Celsius shifted by 273.15 and Fahrenheit is defined through Celsius. Showing all three lets you sanity check the result and read it in whichever unit you think in. Water freezes at 32 F, 0 C, and 273.15 K, and boils at 212 F, 100 C, and 373.15 K.

Kelvin is the SI base unit for temperature and is standard in physics, chemistry, and engineering, where calculations need an absolute scale with no negative values. You will see it for gas laws, thermodynamics, color temperature of light, and astronomy. Fahrenheit stays common for everyday weather and cooking in the United States.