0 K equals -459.67 °F. 100 K equals -279.67 °F.
| Kelvin (K) | Fahrenheit (°F) |
|---|---|
| 233.15 K | -40 °F |
| 253.15 K | -4 °F |
| 263.15 K | 14 °F |
| 273.15 K | 32 °F |
| 283.15 K | 50 °F |
| 293.15 K | 68 °F |
| 303.15 K | 86 °F |
| 310.15 K | 98.6 °F |
| 323.15 K | 122 °F |
| 373.15 K | 212 °F |
| 473.15 K | 392 °F |
| 773.15 K | 932 °F |
Temperature scales use fixed reference points rather than multiplicative factors, so converting between them requires a formula rather than simple multiplication. The Kelvin and Fahrenheit scales differ in both their zero point and the size of their degrees.
For example: 273.15 K = 32 °F, and 373.15 K = 212 °F.
To convert in the reverse direction (Fahrenheit to Kelvin): K = (°F − 32) × 5/9 + 273.15
The Kelvin (K) is the SI base unit of thermodynamic temperature, named after William Thomson (Lord Kelvin), the Belfast-born physicist who first proposed an absolute temperature scale in 1848. Unlike Celsius or Fahrenheit, the Kelvin scale starts at absolute zero — the lowest theoretically possible temperature, defined as 0 K (equal to −273.15°C). There is no negative temperature on the Kelvin scale in the classical thermodynamic sense.
The Kelvin scale is essential in physics and chemistry because thermodynamic laws are expressed in terms of absolute temperature. The ideal gas law (PV = nRT), the Stefan-Boltzmann law for black-body radiation, and the Boltzmann factor in statistical mechanics all require temperature in Kelvin. A gas at 300 K has twice the thermal energy of the same gas at 150 K — a ratio that has no simple physical meaning in Celsius or Fahrenheit.
Since 2019, the Kelvin has been redefined in terms of the Boltzmann constant (k = 1.380649 × 10⁻²³ J/K), fixing the relationship between temperature and energy at the most fundamental level. The degree symbol is not used with Kelvin — you write 273.15 K, not 273.15°K. Temperatures of practical interest range from just above 0 K (ultracold experiments with Bose-Einstein condensates reach billionths of a kelvin) to millions of kelvin (stellar interiors and nuclear fusion reactors).
The Fahrenheit scale was proposed by German physicist Daniel Gabriel Fahrenheit in 1724. His original zero point was set to the lowest temperature he could achieve with a mixture of ice, water, and ammonium chloride (a freezing brine), and 96°F was intended to correspond to human body temperature (later revised to 98.6°F as the scale was refined). Water freezes at 32°F and boils at 212°F under standard conditions — a 180-degree span between those reference points.
Today, Fahrenheit is the official temperature scale for everyday use in the United States, the Cayman Islands, Liberia, and a handful of other jurisdictions. The US National Weather Service reports temperatures in Fahrenheit; US cooking recipes specify oven temperatures in Fahrenheit; and American climate discussions refer to heatwaves breaking 100°F. Most Americans have an intuitive sense of Fahrenheit temperatures the way most of the world has for Celsius.
One argued advantage of Fahrenheit over Celsius for weather reporting is that the 0–100°F range maps more neatly onto typical human weather experience: near 0°F is very cold, near 100°F is very hot, and the middle (50°F) is a cool but livable day. In Celsius, that same experience runs from about −18°C to 38°C, numbers that feel less naturally centered on human experience. This is likely one reason the Fahrenheit scale has been culturally resilient despite metrication pressure.
Use the formula: °F = (K − 273.15) × 9/5 + 32. For example, 0 K = -459.67 °F and 100 K = -279.67 °F.
0 K equals -459.67 °F.
100 K equals -279.67 °F.