Convert Fahrenheit to Kelvin
Fahrenheit to Kelvin turns an everyday US temperature reading into the absolute scale used throughout science. It's the most involved of the temperature conversions, since it has to undo Fahrenheit's scaling and offset before applying Kelvin's own offset.
Fahrenheit to Kelvin conversion table
| Fahrenheit (°F) | Kelvin (K) |
|---|---|
| 1 | 255.927778 |
| 2 | 256.483333 |
| 3 | 257.038889 |
| 5 | 258.15 |
| 10 | 260.927778 |
| 20 | 266.483333 |
| 50 | 283.15 |
| 100 | 310.927778 |
| 500 | 533.15 |
| 1,000 | 810.927778 |
The formula
To convert Fahrenheit to Kelvin, subtract 32, multiply by 5/9, then add 273.15:
K = (°F − 32) × 5/9 + 273.15
This formula does two jobs at once. The (°F − 32) × 5/9 part converts Fahrenheit to Celsius, undoing Fahrenheit's offset and rescaling its smaller degrees into Celsius-sized ones. The + 273.15 then shifts that Celsius value onto Kelvin's absolute scale, which starts at absolute zero rather than at water's freezing point.
Worked example: Convert a room-temperature 68°F to Kelvin:
(68 − 32) × 5/9 + 273.15 = 36 × 5/9 + 273.15 = 20 + 273.15 = 293.15 K
Three anchor points worth knowing: 32°F = 273.15 K (water freezes), 212°F = 373.15 K (water boils), and −459.67°F = 0 K (absolute zero, the coldest temperature there is).
You'll reach for this conversion when translating a US weather or oven reading into the absolute scale that scientific formulas and lab equipment expect.
Frequently asked questions
What is the Fahrenheit to Kelvin formula?
K = (°F − 32) × 5/9 + 273.15. The (°F − 32) × 5/9 part converts Fahrenheit to Celsius first, and the + 273.15 then shifts that onto the Kelvin scale.
What is 32°F in Kelvin?
273.15 K — water's freezing point. Working through the formula: (32 − 32) × 5/9 + 273.15 = 0 + 273.15 = 273.15 K, which also confirms 0°C matches 273.15 K exactly.
What is −459.67°F in Kelvin?
0 K — absolute zero, the coldest temperature that exists. It's the one point where Fahrenheit, Celsius, and Kelvin all describe the same physical reality, which makes it a handy way to sanity-check the formula.