Temperature Converter
Convert between Celsius, Fahrenheit and Kelvin. Temperature scales have different zero points, so the conversion uses proper formulas rather than a simple multiplier.
Result
Enter a value to convert.
How to use this calculator
- Enter a temperature (negative values are allowed).
- Choose the from and to scales.
- Values below absolute zero are rejected because they are physically impossible.
Formula
°F = °C × 9/5 + 32°C = (°F − 32) × 5/9K = °C + 273.15°C = K − 273.15
Absolute zero is 0 K = −273.15 °C = −459.67 °F.
Worked example
25 °C in Fahrenheit
25 × 9/5 + 32 = 45 + 32 = 77 °F.
98.6 °F in Celsius
(98.6 − 32) × 5/9 = 66.6 × 5/9 = 37 °C.
300 K in Celsius
300 − 273.15 = 26.85 °C.
Assumptions and limitations
- Kelvin has no degree symbol and cannot be negative.
- Converting a temperature difference (for example “a rise of 10 °C”) is not the same as converting a temperature: a 10 °C change equals an 18 °F change.
Frequently asked questions
At what temperature are Celsius and Fahrenheit equal?
At −40. −40 °C is exactly −40 °F.
Why can’t I just multiply to convert temperatures?
The scales start at different zero points, so an offset has to be added or subtracted as well as scaling. Multiplying alone gives the wrong answer.