Degrees Fahrenheit to kelvins converter

How to convert Fahrenheit to Kelvin

Add 459.67 to the Fahrenheit reading, then multiply by 5/9: K = (°F + 459.67) × 5/9. So 68 °F is 527.67 × 5/9 = 293.15 K, and 32 °F is 273.15 K. Use it when a US temperature has to go into a physics or chemistry formula.

Where 459.67 and 5/9 come from

Absolute zero is −459.67 °F, so adding 459.67 counts degrees up from absolute zero. That intermediate number is the Rankine scale: 68 °F is 527.67 °R.

A Fahrenheit degree is 5/9 the size of a kelvin, so multiplying by 5/9 turns Rankine into kelvins. Going through Celsius gives the same answer: K = (°F − 32) × 5/9 + 273.15 (NIST).

Fahrenheit to Kelvin chart

0 °F is 255.372222… K, a repeating decimal shown rounded; the other rows are exact. −459.67 °F is absolute zero, so no reading goes lower.

Worked examples

• Body temperature: (98.6 + 459.67) × 5/9 = 558.27 × 5/9 = 310.15 K.
• A cool morning: (50 + 459.67) × 5/9 = 509.67 × 5/9 = 283.15 K.
• Oven at 350 °F: (350 + 459.67) × 5/9 = 809.67 × 5/9 = 449.82 K.

Temperature changes use 5/9 only

A change has no zero point to move, so skip the 459.67. A rise of 18 °F is a rise of 18 × 5/9 = 10 K.

Warming from 32 °F to 50 °F takes the kelvin reading from 273.15 K to 283.15 K: the same 10 K.

Common mistakes

• Multiplying before adding. 68 × 5/9 + 459.67 gives 497.45, about 204 K too high. Add 459.67 first, inside the parentheses.
• Adding 273.15 to the Fahrenheit number. 68 + 273.15 = 341.15 K, 48 K too high. The 273.15 offset only applies to Celsius.
• Rounding 459.67 to 460. Every result lands 0.18 K high: 68 °F becomes 293.33 K.
• Using 9/5. That ratio belongs to the kelvin-to-Fahrenheit direction; (68 + 459.67) × 9/5 gives 949.81 K.

Related temperature conversions

The Kelvin to Fahrenheit converter reverses the steps, Fahrenheit to Celsius stops at the everyday metric scale, and the ideal gas law calculator takes the kelvin result straight into PV = nRT.