Fahrenheit to Kelvin
One °F equals 255.9277778 K. Type any number and the answer appears as you type — the maths happens in your browser.
The same value in every unit
| Unit | Value |
|---|
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Common values
| Fahrenheit | Kelvin |
|---|---|
| -40 °F | 233.15 K |
| -20 °F | 244.26111 K |
| -10 °F | 249.81667 K |
| 0 °F | 255.37222 K |
| 10 °F | 260.92778 K |
| 20 °F | 266.48333 K |
| 25 °F | 269.26111 K |
| 30 °F | 272.03889 K |
| 37 °F | 275.92778 K |
| 50 °F | 283.15 K |
| 100 °F | 310.92778 K |
| 200 °F | 366.48333 K |
How to use
- Enter the number of Fahrenheit in the field.
- The result in Kelvin updates on every keystroke.
- Use the table below for the values people look up most often.
Formula and reverse conversion
The formula
To convert by hand: K = (°F − 32) × 5/9 + 273.15. Going back the other way, one K is -457.87 °F.
Why you cannot just multiply
Celsius, Fahrenheit and Kelvin start counting from different points, so a temperature is converted with a formula rather than a factor. That is why −40 is the same number in Celsius and Fahrenheit, and why a difference between two temperatures converts differently from a temperature itself.
K = (°F − 32) × 5/9 + 273.15
Frequently asked questions
How many Kelvin are in one Fahrenheit?
One °F is 255.9277778 K.
How do I convert Fahrenheit to Kelvin?
Multiply by the factor: K = (°F − 32) × 5/9 + 273.15.
Is the result exact?
The factors are the exact legal definitions, and up to ten significant digits are kept in the answer. Rounding happens only in the display.
How do I convert Kelvin back to Fahrenheit?
One K is -457.87 °F — or open the reverse page linked below.