Convert Kelvin to Fahrenheit
Fahrenheit = Kelvin × 1.8 − 459.67. Type any temperature below to convert kelvin to fahrenheit both ways — it runs entirely in your browser.
Kelvin to Fahrenheit formula
Temperature scales have different zero points, so the conversion is a multiply-and-add, not a single ratio:
Fahrenheit = Kelvin × 1.8 − 459.67
To go the other way, Kelvin = Fahrenheit × 0.5555556 + 255.3722.
Worked example
Convert 300 K to fahrenheit:
= 300 × 1.8 − 459.67 = 80.33 °F.
Common temperatures in Kelvin and Fahrenheit
| Reference point | Kelvin (K) | Fahrenheit (°F) |
|---|---|---|
| Absolute zero | 0 | -459.67 |
| Freezing point of water | 273.15 | 32 |
| Refrigerator | 277.15 | 39.2 |
| Room temperature | 294.15 | 69.8 |
| Normal human body temperature | 310.15 | 98.6 |
| A hot summer day | 318.15 | 113 |
| Boiling point of water (sea level) | 373.15 | 212 |
About the Kelvin and Fahrenheit scales
Kelvin: The kelvin is the SI base unit of temperature. It starts at absolute zero (0 K = −273.15 °C) and uses the same degree size as Celsius, so it is written without a degree sign.
Fahrenheit: Fahrenheit puts water’s freezing point at 32° and its boiling point at 212° — a 180-degree span. It is the everyday scale in the United States and a few other territories.
Sources
- NIST Special Publication 811 — Guide for the Use of the SI — publishes the defining relations between the temperature scales. Unlike every other conversion on this site these are affine, not a single multiplying factor: t/°C = (t/°F − 32)/1.8 and T/K = (T/°R)/1.8 are exact by definition, so the figures here are exact rather than rounded — the scales simply have different zero points as well as different degree sizes.
- BIPM — The International System of Units (SI Brochure) — the defining document for the SI, published by the International Bureau of Weights and Measures. It fixes the base unit that this conversion resolves to, which is why the factor here can be exact rather than approximate.
Frequently asked questions
- What is 300 K in Fahrenheit?
- 300 K = 80.33 °F.
- How do I convert Kelvin to Fahrenheit?
- Use fahrenheit = kelvin × 1.8 − 459.67. For example, 300 K → 80.33 °F.
- How do I convert Fahrenheit back to Kelvin?
- Reverse it: kelvin = fahrenheit × 0.5555556 + 255.3722.
- Why isn't converting Kelvin to Fahrenheit just multiplication?
- Because the two scales start their zero at different temperatures, so after scaling by 1.8 you also subtract 459.67. Skipping that constant is the most common temperature-conversion mistake.