This degrees Fahrenheit to kelvin converter turns any °F reading into K instantly, in your browser, with the formula shown so you can check the result by hand. Degrees Fahrenheit are a US customary unit; kelvin are an SI unit used in science and engineering. Water freezes at 32 °F (273.15 K) and boils at 212 °F (373.15 K) at sea level.
The formula is K = (°F − 32) × 5/9 + 273.15. For a quick mental estimate between Celsius and Fahrenheit, double the Celsius value and add 30; it is within a few degrees for everyday temperatures. Normal body temperature is 98.6 °F, which is 310.15 K.
°F to K formula
K = (°F − 32) × 5/9 + 273.15
Degrees Fahrenheit to Kelvin conversion table
| degrees Fahrenheit | kelvin | Rounded |
|---|---|---|
| -40 °F | 233.15 K | 233 |
| -30 °F | 238.706 K | 239 |
| -20 °F | 244.261 K | 244 |
| -10 °F | 249.817 K | 25 |
| 0 °F | 255.372 K | 255 |
| 10 °F | 260.928 K | 261 |
| 20 °F | 266.483 K | 266 |
| 25 °F | 269.261 K | 269 |
| 30 °F | 272.039 K | 272 |
| 37 °F | 275.928 K | 276 |
| 40 °F | 277.594 K | 278 |
| 50 °F | 283.15 K | 283 |
| 60 °F | 288.706 K | 289 |
| 70 °F | 294.261 K | 294 |
| 80 °F | 299.817 K | 3 |
| 90 °F | 305.372 K | 305 |
| 100 °F | 310.928 K | 311 |
| 150 °F | 338.706 K | 339 |
| 200 °F | 366.483 K | 366 |
| 250 °F | 394.261 K | 394 |
| 300 °F | 422.039 K | 422 |
| 350 °F | 449.817 K | 45 |
| 400 °F | 477.594 K | 478 |
| 450 °F | 505.372 K | 505 |
Frequently asked questions
How many kelvin are in 20 degrees Fahrenheit?
20 °F = 266.483 K. Apply the formula K = (°F − 32) × 5/9 + 273.15. The converter on this page does the same arithmetic for any value, including decimals.
What is the formula to convert degrees Fahrenheit to kelvin?
K = (°F − 32) × 5/9 + 273.15. Temperature scales have different zero points, so you cannot simply multiply; the offset matters. Worked example: 100 °F = 310.928 K.
Is -10 °F the same as 249.817 K?
Yes. -10 °F = 249.817 K, a common winter temperature. Notice that -40 is the one point where Celsius and Fahrenheit agree: -40 °C equals -40 °F.
How do I convert kelvin back to degrees Fahrenheit?
Reverse the formula: °F = (K − 273.15) × 9/5 + 32. Or use the kelvin to degrees Fahrenheit page linked above, which has its own table and examples.