Fahrenheit to Kelvin (F to K) Converter and Formula
To convert Fahrenheit to Kelvin, use K = (°F − 32) × 5/9 + 273.15. For example, 100 °F = (100 − 32) × 5/9 + 273.15 = 310.927778 K. You first convert to Celsius, then add 273.15 because Kelvin starts at absolute zero.
The formula
Subtract 32, scale by 5/9, then add 273.15:
K = (°F − 32) × 5/9 + 273.15
Example: (32 − 32) × 5/9 + 273.15 = 273.15 KTo reverse it, use °F = (K − 273.15) × 9/5 + 32.
Conversion table
| Fahrenheit (°F) | Kelvin (K) |
|---|---|
| -40 | 233.15 |
| 0 | 255.372222 |
| 32 | 273.15 |
| 50 | 283.15 |
| 68 | 293.15 |
| 72 | 295.372222 |
| 98.6 | 310.15 |
| 100 | 310.927778 |
| 212 | 373.15 |
| 350 | 449.816667 |
How to convert online
- Type the Fahrenheit temperature into the first box.
- Read the Kelvin value instantly in the second box.
- Or enter a Kelvin value to convert back to Fahrenheit — it works both ways.
Use the Fahrenheit to Kelvin Converter — free and instant in your browser.
Where this conversion is used
Kelvin is the SI base unit of temperature, so this conversion matters in physics, chemistry, thermodynamics and engineering, where absolute temperature is required for gas laws, blackbody radiation and thermal calculations. Converting from everyday Fahrenheit readings to Kelvin lets US-based measurements feed directly into scientific formulas.
FAQ
What is 100 °F in Kelvin?
100 °F equals 310.927778 K.
What is the formula to convert Fahrenheit to Kelvin?
K = (°F − 32) × 5/9 + 273.15. Convert to Celsius first, then add 273.15.
What is 0 °F in Kelvin?
Zero °F equals 255.372222 K. Kelvin has no negative values because it starts at absolute zero.
How do I convert Kelvin back to Fahrenheit?
Use °F = (K − 273.15) × 9/5 + 32, or use our reverse converter for matching numbers.
Related converters
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Recommended reading
Kelvin to Fahrenheit (K to °F) Converter
Kelvin to Fahrenheit: °F = (K − 273.15) × 9/5 + 32. So 300 K = 80.33 °F. Free instant converter with the exact formula and a reference table.
Kelvin to Celsius (K to °C) Converter
Kelvin to Celsius: subtract 273.15. °C = K − 273.15, so 300 K = 26.85 °C. Free instant converter with the exact formula and a reference table.
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Convert Fahrenheit to Celsius with C = (F-32) x 5/9. 100F = 37.78C. Full formula, conversion table and instant two-way converter in your browser.
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Convert Celsius to Kelvin with the exact formula K = °C + 273.15. 100 °C = 373.15 K. Free reference table, worked examples and instant online tool.