Type a value into Celsius, Fahrenheit or Kelvin and watch the other two update instantly — with quick reference points to help it all make sense.
Type into any field below.
Formulas used: °F = °C × 9/5 + 32, and K = °C + 273.15.
See where your value lands.
Every field is a live input — edit Fahrenheit or Kelvin just as easily as Celsius.
Anything below absolute zero is flagged instantly instead of silently showing a wrong answer.
Everything is calculated locally in your browser. Nothing you type is stored or sent anywhere.
This free online temperature converter keeps Celsius, Fahrenheit and Kelvin in sync at all times, so you never need to pick a direction first.
Celsius and Kelvin share the same size of degree, just offset by 273.15, since 0 Kelvin (absolute zero) is defined as -273.15°C. Fahrenheit uses a smaller degree and a different zero point, which is why its conversion formula involves both a multiplication and an addition.
Multiply the Celsius value by 9/5 (or 1.8), then add 32. To go the other way, subtract 32 first, then multiply by 5/9.
Simply add 273.15 to the Celsius value. Subtract 273.15 from Kelvin to get back to Celsius.
Convert Fahrenheit to Celsius first, then add 273.15 — there's no single-step shortcut between the two.
Nothing can be colder than -273.15°C (-459.67°F, 0K), the point at which particles have minimal thermal motion.
Quick answers about the formulas, limits and privacy of this tool.
Fahrenheit equals Celsius multiplied by 9/5, plus 32. This converter applies that formula (and its reverse) instantly as you type.
Kelvin equals Celsius plus 273.15. Kelvin uses the same size degree as Celsius, just shifted so that 0 Kelvin is absolute zero.
Absolute zero, equal to -273.15°C, -459.67°F or 0 Kelvin, is the coldest temperature theoretically possible. This converter flags any value entered below that point.
Yes. Celsius, Fahrenheit and Kelvin are all live input fields. Typing a number into any one of them instantly recalculates the other two.
No. All conversion happens locally in your browser. Nothing you type here is stored or transmitted.