Freezing reference
0°C equals 32°F and 273.15 K.
Convert temperatures precisely between Celsius, Fahrenheit, and Kelvin, with reference values and physical absolute-zero validation.
The shared conversion engine first converts the source temperature to Celsius, then converts that Celsius value to the target scale. This provides one consistent source of truth for every scale pair.
Unlike length and mass units, temperature scales have different zero points as well as different interval sizes. Their conversions therefore require offsets, not only multiplication.
°F = °C × 9/5 + 32°C = (°F − 32) × 5/9K = °C + 273.15°C = K − 273.15K = (°F − 32) × 5/9 + 273.15°F = (K − 273.15) × 9/5 + 320°C equals 32°F and 273.15 K.
100°C equals 212°F and 373.15 K at standard atmospheric pressure.
−40°C equals −40°F.
300 K equals approximately 26.85°C and 80.33°F.
Celsius uses 0°C and 100°C as familiar water freezing and boiling references at standard atmospheric pressure.
Fahrenheit places the same reference points at 32°F and 212°F.
Kelvin is an absolute thermodynamic scale. Its zero is absolute zero and the unit symbol does not use a degree sign.
Absolute zero is 0 K, equivalent to −273.15°C and −459.67°F. The calculator rejects lower inputs instead of silently clamping them.
−40°C equals −40°F; 0°C equals 32°F; 20°C equals 68°F; 37°C is approximately 98.6°F; and 100°C equals 212°F. Room temperature varies, so 20°C is only a convenient reference.
Multiply Celsius by 9/5, then add 32.
Subtract 32 from Fahrenheit, then multiply by 5/9.
Add 273.15 to the Celsius temperature.
Absolute zero is 0 K, equal to −273.15°C or −459.67°F.
A thermodynamic Kelvin temperature cannot be below 0 K, so this calculator rejects negative Kelvin inputs.
The scales have the same numeric value at −40 degrees.
20°C equals 68°F, a common reference, but actual room temperatures vary.
Temperature scales differ in both interval size and zero point, so their formulas require an offset.