Fahrenheit to Kelvin (°F to K)
Result
255.9277778 Kelvin
Formula
K = °F × 0.5555555556 + 255.3722222
The kelvin is the SI base unit, defined through the Boltzmann constant. A Celsius temperature is the kelvin temperature minus 273.15, and a Fahrenheit degree is 5/9 of a Celsius degree with water freezing at 32 °F. Rankine uses Fahrenheit-sized degrees from absolute zero.
Worked examples
- 1 °F × 0.5555555556 + 255.3722222 = 255.92778 K
- 10 °F × 0.5555555556 + 255.3722222 = 260.92778 K
- 100 °F × 0.5555555556 + 255.3722222 = 310.92778 K
Common mistakes
- Temperature readings and temperature differences convert differently: a reading uses °F = °C × 9/5 + 32, but a change of 10 °C is a change of 18 °F (no +32).
- −40 is the same reading in °C and °F; the popular "double it and add 30" shortcut drifts several degrees away from about 10 °C.
- Kelvin is written without a degree sign (300 K) and cannot be negative.
Fahrenheit to Kelvin table
| Fahrenheit (°F) | Kelvin (K) |
|---|---|
| 1 | 255.92778 |
| 2 | 256.48333 |
| 5 | 258.15 |
| 10 | 260.92778 |
| 20 | 266.48333 |
| 50 | 283.15 |
| 100 | 310.92778 |
| 1,000 | 810.92778 |
The units
- Fahrenheit (°F)
- Fahrenheit: degrees 5/9 the size of Celsius degrees, with water freezing at 32 °F and boiling at 212 °F at sea level.
- Kelvin (K)
- The kelvin, the SI base unit of temperature, measured from absolute zero. A kelvin is the same size as a Celsius degree.
Sources for these factors
- The International System of Units (SI Brochure), 9th edition — BIPM
- Guide for the Use of the International System of Units (SP 811), Appendix B: conversion factors — NIST
- Handbook 44 (2024), Appendix C: General Tables of Units of Measurement — NIST
Last reviewed against these sources. An automated check recomputes every factor from its definition on each build. How we check accuracy