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Temperature Converter
Convert Celsius, Fahrenheit and Kelvin at a glance — no button to press.
Why isn't temperature conversion just a multiplication?
Unlike length or weight, temperature scales don't share a common zero point, so converting between them means both scaling and shifting the number, not just multiplying by a factor. Celsius sets 0° at water's freezing point and 100° at its boiling point (at sea level). Fahrenheit, still standard in the US for weather and cooking, sets water's freezing point at 32° and boiling point at 212°. Kelvin, used in science and engineering, starts at absolute zero (−273.15°C) and uses the same size degree as Celsius — which is why a Kelvin reading is always exactly 273.15 higher than the same temperature in Celsius.
This converter runs the correct formula for each direction — Celsius to Fahrenheit, Fahrenheit to Kelvin, and every other combination — and shows all three scales for the value you entered, so you never have to remember which formula goes which way.
Frequently asked questions
How do I convert Celsius to Fahrenheit?
Multiply the Celsius value by 9/5 and add 32: F = C × 9/5 + 32. For example, 20°C equals 68°F.
How do I convert Fahrenheit to Celsius?
Subtract 32 from the Fahrenheit value, then multiply by 5/9: C = (F − 32) × 5/9. For example, 98.6°F equals 37°C.
What is 0 Kelvin in Celsius?
0 Kelvin (absolute zero, the coldest possible temperature) equals −273.15°C. To convert Kelvin to Celsius, subtract 273.15.
Why does Kelvin have no negative numbers?
Kelvin is an absolute scale that starts at absolute zero, the theoretical point where all thermal motion stops — so there is no temperature below 0 K, and the scale never needs a negative sign.