What this calculator does
This tool converts a temperature given in degrees Fahrenheit (°F) to Kelvin (K), the SI base unit of thermodynamic temperature. Kelvin starts at absolute zero — the coldest possible temperature — so it is never written with a degree symbol and never goes below 0.
How to use it
Type your Fahrenheit temperature into the input box. Decimals and negative numbers are accepted (for example −40 °F). Press calculate to see the exact Kelvin value, a friendly rounded value, and a three-step breakdown of the math.
The formula explained
The conversion is $$K = (\degree F + 459.67) \times \frac{5}{9}$$ Absolute zero sits at −459.67 °F, so adding 459.67 first shifts the reading onto an absolute (Rankine-style) scale. Multiplying by \(\frac{5}{9}\) — the same as dividing by \(1.8\) — rescales the larger Fahrenheit degree into the smaller Kelvin degree.
Worked example
Convert 82 °F:
$$K = (82 + 459.67) \times \frac{5}{9}$$
$$K = 541.67 \times 5 \div 9$$
$$K = 2708.35 \div 9$$
$$K = 300.9278 \text{ K}$$ which rounds to about 301 K.
FAQ
What is 32 °F in Kelvin? Water freezes at 32 °F = 273.15 K. Boiling water is 212 °F = 373.15 K.
Can Kelvin be negative? No. The Kelvin scale begins at absolute zero (0 K). Any Fahrenheit value below −459.67 °F gives a non-physical negative result, which this calculator flags with a warning.
Is multiplying by 5/9 the same as dividing by 1.8? Yes, exactly. \(\frac{5}{9} = 0.5556\) and \(\frac{1}{1.8} = 0.5556\), so both forms give the identical answer.
