Kelvin to Fahrenheit Converter (K to °F)
°F = K × 9/5 − 459.67. Convert kelvins to Fahrenheit for space missions, planets and lab data, with K to °F and °F to K charts.
°F = K × 9/5 − 459.67
Kelvin (K): The kelvin is the SI base unit of thermodynamic temperature, defined since 2019 by fixing the Boltzmann constant at exactly 1.380649 × 10⁻²³ J/K. The scale starts at absolute zero (0 K), and 0 °C is exactly 273.15 K.
Fahrenheit (°F): Fahrenheit temperature is defined by °F = °C × 9/5 + 32. Thus 0 °C equals exactly 32 °F, 100 °C equals exactly 212 °F, and absolute zero is −459.67 °F.
| Kelvin (K) | Fahrenheit (°F) |
|---|---|
| 1 | -457.87 |
| 5 | -450.67 |
| 10 | -441.67 |
| 25 | -414.67 |
| 50 | -369.67 |
| 100 | -279.67 |
Spacecraft specifications, planetary science and physics news give temperatures in kelvins, and American readers usually want them in Fahrenheit. The formula multiplies by 9/5, because a kelvin is 1.8 Fahrenheit degrees, and then subtracts 459.67, the Fahrenheit reading of absolute zero. Every reading below about 255.37 K comes out below 0 °F.
Space hardware shows why the conversion matters. The Webb telescope's instruments have to stay below about 50 K, which is roughly −370 °F, and its mid-infrared instrument runs colder still, below 7 K. Planet surfaces vary just as widely, from Earth's average near 288 K, close to 59 °F, to about 737 K on Venus, near 867 °F and hot enough to melt lead.
How to use this tool
- Type a value in the Kelvin box to see it in degrees Fahrenheit, or type in the Fahrenheit box to convert the other way.
- Press ⇄ to swap the two units, or Load example for a typical value.
- Check the charts below for common values; for other units, open the Temperature converter.
Formula
°F = K × 9/5 − 459.67
K = (°F + 459.67) × 5/9
The scales have different zero points, so the formula adds or subtracts an offset as well as multiplying.
Example
Two conversions worked with the same factors the converter uses:
50 K = -369.67 °F
-320 °F ≈ 77.5944 K
Kelvin to Fahrenheit chart
Common values from kelvins to degrees Fahrenheit, rounded to four decimal places.
| Kelvin (K) | Fahrenheit (°F) |
|---|---|
| 0 | -459.67 |
| 1 | -457.87 |
| 2.725 | -454.765 |
| 4 | -452.47 |
| 7 | -447.07 |
| 10 | -441.67 |
| 20 | -423.67 |
| 50 | -369.67 |
| 77 | -321.07 |
| 100 | -279.67 |
| 150 | -189.67 |
| 183.95 | -128.56 |
| 200 | -99.67 |
| 250 | -9.67 |
| 273.15 | 32 |
| 288 | 58.73 |
| 293.15 | 68 |
| 300 | 80.33 |
| 373.15 | 212 |
| 500 | 440.33 |
| 737 | 866.93 |
| 1,000 | 1,340.33 |
| 1,811 | 2,800.13 |
| 3,000 | 4,940.33 |
Fahrenheit to Kelvin chart
The reverse direction for values people often look up.
| Fahrenheit (°F) | Kelvin (K) |
|---|---|
| -459.67 | 0 |
| -400 | 33.15 |
| -320 | 77.5944 |
| -100 | 199.8167 |
| -40 | 233.15 |
| 0 | 255.3722 |
| 32 | 273.15 |
| 70 | 294.2611 |
| 100 | 310.9278 |
| 212 | 373.15 |
| 451 | 505.9278 |
| 1,000 | 810.9278 |
Space and planetary temperatures in kelvins
| Object | Kelvin (K) | Fahrenheit (°F) |
|---|---|---|
| Afterglow of the Big Bang (CMB), about | 2.725 | -454.765 |
| Webb's mid-infrared instrument, kept below about | 7 | -447.07 |
| Liquid hydrogen rocket fuel boils, about | 20 | -423.67 |
| Lowest air temperature recorded on Earth (Vostok) | 183.95 | -128.56 |
| Earth, average surface temperature, about | 288 | 58.73 |
| Venus, average surface temperature, about | 737 | 866.93 |
| Iron melts, about | 1,811 | 2,800.13 |
Quick mental estimate
Double the kelvins, take away a tenth of the result, then subtract 460: 300 K → 600 − 60 = 540, and 540 − 460 = 80 °F, against an exact 80.33 °F. Doubling and removing a tenth is exactly 1.8; only rounding 459.67 to 460 costs a third of a degree.
Use the converter or the charts when the exact figure matters.
The two units
Kelvin (K): The kelvin is the SI base unit of thermodynamic temperature, defined since 2019 by fixing the Boltzmann constant at exactly 1.380649 × 10⁻²³ J/K. The scale starts at absolute zero (0 K), and 0 °C is exactly 273.15 K.
Fahrenheit (°F): Fahrenheit temperature is defined by °F = °C × 9/5 + 32. Thus 0 °C equals exactly 32 °F, 100 °C equals exactly 212 °F, and absolute zero is −459.67 °F.
Frequently asked questions
Why do space temperatures look so extreme in Fahrenheit?
The Fahrenheit degree is smaller than a kelvin and its zero sits 459.67 degrees above absolute zero, so cold readings become large negative numbers. A reading of 100 K becomes about −280 °F.
At what temperature do kelvins and Fahrenheit show the same number?
At 574.5875. Setting K × 9/5 − 459.67 equal to K gives K = 459.67 × 5/4, so 574.5875 K is also 574.5875 °F; below that point the Fahrenheit figure is the smaller one.
Is kelvin to Fahrenheit the same as Rankine?
Not quite. Multiplying kelvins by 1.8 gives degrees Rankine, an absolute scale with Fahrenheit-sized degrees, and subtracting 459.67 then turns Rankine into Fahrenheit. The temperature converter shows all three.
How precise is the result?
The converter uses the exact definitions above with browser floating-point arithmetic and shows up to 12 significant digits. The charts round to four decimal places for reading.
Sources
Last updated:
Page address with these inputs: https://kakao.mobile/tools/kelvin-to-fahrenheit-converter/
Cite or embed this tool
kakaoCalc. (2026, November 8). Kelvin to Fahrenheit Converter (K to °F). https://kakao.mobile/tools/kelvin-to-fahrenheit-converter/
“Kelvin to Fahrenheit Converter (K to °F).” kakaoCalc, 8 Nov. 2026, kakao.mobile/tools/kelvin-to-fahrenheit-converter/.
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