Recipes in Fahrenheit, weather in Celsius, physics in Kelvin — temperature is the unit we translate most often. This temperature converter changes any value between Celsius, Fahrenheit and Kelvin instantly: type in one scale and read all three.
How to convert Celsius to Fahrenheit
Multiply by 9/5 (or 1.8) and add 32: °F = °C × 9/5 + 32. So 20 °C is 68 °F, and 180 °C — a common oven temperature — is 356 °F. Going the other way, subtract 32 first, then multiply by 5/9: 98.6 °F − 32 = 66.6, × 5/9 = 37 °C, normal body temperature.
Kelvin: the scientific scale
Kelvin is the SI base unit of temperature, offset from Celsius by exactly 273.15 with the same step size: K = °C + 273.15. Zero kelvin (−273.15 °C) is absolute zero — the point at which molecular motion is minimal. There are no negative Kelvin temperatures, which is why science uses it.
Reference points worth memorizing
Water freezes at 0 °C = 32 °F = 273.15 K, and boils at 100 °C = 212 °F (at sea level). Room temperature is about 20–22 °C (68–72 °F); body temperature ~37 °C (98.6 °F). And a great trivia fact: −40° is where Celsius and Fahrenheit read exactly the same.
Quick mental estimates
For Celsius → Fahrenheit on the fly, double it and add 30 (20 °C → ~70 °F; exact is 68). For Fahrenheit → Celsius, subtract 30 and halve. These get you within a degree or two across everyday weather ranges — use the converter when you need it exact. Converting other units too? Try the length, weight and speed converters.