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Convert °F to K
K = (°F − 32) × 5/9 + 273.15
Type a value in degrees Fahrenheit and the answer in kelvin appears as you go. The conversion is a scale change rather than a simple factor, which is why the formula below has a shift in it, and it happens on your own machine — this page asks nothing of a server once it has loaded.
Where it runs
In your browser. The number you type is never part of a request.
A scale, not a factor
Fahrenheit and Kelvin start at different zeros, so the conversion shifts as well as scales.
Answers as you type
No button, no wait. The worked answer is already on the page before any script runs.
Fahrenheit and Kelvin
Fahrenheit puts freezing at 32 and boiling at 212, so a Fahrenheit degree is five ninths the size of a Celsius one. That difference in size is why the conversion needs a multiplication and not just a shift.
Kelvin starts at absolute zero, the point where there is no thermal energy left to remove, and its degrees are the same size as Celsius ones. It takes no degree sign — it is 300 K, not 300 °K.
degrees Fahrenheit to kelvin in practice
350 °F is 449.8 K
— a moderate oven, as an American recipe writes it.
98.6 °F is 310.1 K
— the traditional figure for body temperature.
degrees Fahrenheit to kelvin at a glance
| °F | K |
|---|---|
| 0 | 255.372222222 |
| 32 | 273.15 |
| 50 | 283.15 |
| 68 | 293.15 |
| 86 | 303.15 |
| 100 | 310.927777778 |
| 212 | 373.15 |
Every figure here is computed from the same definition the calculator uses, so the table cannot drift away from the answer above it.
Convert °F to K: common questions
How many kelvin are in a fahrenheit?
It depends where you start, which is what makes temperature different from every other unit here. Fahrenheit and Kelvin do not share a zero, so there is no single number of one in the other — the conversion is K = (°F − 32) × 5/9 + 273.15.
Is this conversion exact, or rounded?
The relationship is exact — K = (°F − 32) × 5/9 + 273.15 is a definition, not a measurement. What is rounded is only the display, which stops at twelve significant figures.
Why does another converter show a slightly different number?
Almost always rounding rather than disagreement. Many converters cut the answer to two or four decimals, and some carry a factor that was rounded before the multiplication rather than after. The figures here are computed from the exact definitions and only rounded on the way to the screen.
Where these figures come from
The claims this page makes about temperature units are checkable, and these are the documents that settle them.
How this page works
The factor is a constant in the page and the arithmetic is four operations, so nothing is sent anywhere and nothing needs to be. The number you type never leaves the browser — there is no request for it to travel in.