Convert Fahrenheit to Kelvin
Kelvin = Fahrenheit × 0.5555556 + 255.3722. Type any temperature below to convert fahrenheit to kelvin both ways — it runs entirely in your browser.
Fahrenheit to Kelvin formula
Temperature scales have different zero points, so the conversion is a multiply-and-add, not a single ratio:
Kelvin = Fahrenheit × 0.5555556 + 255.3722
To go the other way, Fahrenheit = Kelvin × 1.8 − 459.67.
Worked example
Convert 98.6 °F to kelvin:
= 98.6 × 0.5555556 + 255.3722 = 310.15 K.
Common temperatures in Fahrenheit and Kelvin
| Reference point | Fahrenheit (°F) | Kelvin (K) |
|---|---|---|
| Absolute zero | -459.67 | 0 |
| Freezing point of water | 32 | 273.15 |
| Refrigerator | 39.2 | 277.15 |
| Room temperature | 69.8 | 294.15 |
| Normal human body temperature | 98.6 | 310.15 |
| A hot summer day | 113 | 318.15 |
| Boiling point of water (sea level) | 212 | 373.15 |
About the Fahrenheit and Kelvin scales
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.
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.
Frequently asked questions
- What is 98.6 °F in Kelvin?
- 98.6 °F = 310.15 K.
- How do I convert Fahrenheit to Kelvin?
- Use kelvin = fahrenheit × 0.5555556 + 255.3722. For example, 98.6 °F → 310.15 K.
- How do I convert Kelvin back to Fahrenheit?
- Reverse it: fahrenheit = kelvin × 1.8 − 459.67.
- Why isn't converting Fahrenheit to Kelvin just multiplication?
- Because the two scales start their zero at different temperatures, so after scaling by 0.5555556 you also add 255.3722. Skipping that constant is the most common temperature-conversion mistake.