Temperature Converter
Convert between Celsius, Fahrenheit, and Kelvin.
Inputs
Allowed range: -1000000 to 1000000
Results
Celsius
25.00 °C
Fahrenheit
77.00 °F
Kelvin
298.15 K
How it works
C → F: C·9/5 + 32. C → K: C + 273.15.
Complete guide
Three temperature scales dominate the world. Celsius (°C) is the global standard for weather and science, set so water freezes at 0° and boils at 100°. Fahrenheit (°F) is still used for daily life in the United States. Kelvin (K) is the scientific 'absolute' scale, where 0 K = absolute zero (−273.15 °C).
Mental conversion shortcuts: to convert °C to °F roughly, double it and add 30 (close enough for weather). 0 °C = 32 °F, 20 °C = 68 °F (room temp), 37 °C = 98.6 °F (body), 100 °C = 212 °F (boiling water).
Kelvin uses the same unit size as Celsius, so a 5 K change equals a 5 °C change. Only the zero point differs.
Frequently asked questions
- Why does the U.S. use Fahrenheit?
- Historical inertia. Fahrenheit was the dominant English-speaking standard before the metric system spread, and the U.S. never made the switch for everyday weather and cooking.
- Can temperature be negative in Kelvin?
- No. Kelvin starts at absolute zero, the coldest possible temperature, where atomic motion stops. Negative Kelvin is impossible by definition.
- Is Celsius the same as centigrade?
- Yes. 'Centigrade' was the original name; it was officially renamed Celsius in 1948 to honor astronomer Anders Celsius.
- What's the conversion formula?
- °F = °C × 9/5 + 32; °C = (°F − 32) × 5/9; K = °C + 273.15. The calculator handles all six directions automatically.