Convert temperature between Celsius, Fahrenheit, and Kelvin using exact formulas — not rough approximations.
Enter a temperature to convert.
| Celsius | Fahrenheit | Kelvin |
|---|---|---|
| −273.15°C | −459.67°F | 0K |
| −40°C | −40°F | 233.15K |
| 0°C | 32°F | 273.15K |
| 20°C | 68°F | 293.15K |
| 37°C | 98.6°F | 310.15K |
| 100°C | 212°F | 373.15K |
A temperature converter translates a reading from one temperature scale to another so it describes the same physical warmth or cold. Unlike most unit conversions, temperature scales don't just differ by a multiplier — Fahrenheit and Celsius also start counting from different zero points, so converting between them takes a real formula, not a single multiplication.
Used by most of the world for everyday temperatures, weather, and science. Water freezes at 0°C and boils at 100°C at sea level.
Used primarily in the United States. Water freezes at 32°F and boils at 212°F at sea level — a 180-degree span compared to Celsius's 100-degree span, which is why the formulas involve 9/5 (or 5/9 in reverse).
The absolute thermodynamic scale used in science and engineering. Kelvin uses the exact same degree size as Celsius, just shifted so that 0K sits at absolute zero instead of the freezing point of water. Kelvin values are never written with a degree symbol.
Absolute zero — the coldest temperature physically possible — is −273.15°C, −459.67°F, or exactly 0K. Nothing can be colder than this, so unlike converters where a negative value is simply unusual, a temperature colder than absolute zero cannot exist at all. This converter checks every input against absolute zero and shows an error rather than a result if you enter a temperature below it.
Temperature conversions come up when following a recipe or oven setting from another country, checking the weather forecast while traveling, working through science or engineering coursework, reading a thermostat or lab instrument calibrated in an unfamiliar scale, and comparing climate or industrial temperature data reported in different units.
Multiply the Celsius value by 9/5, then add 32: F = C × 9/5 + 32. For example, 20°C × 9/5 + 32 = 68°F.
Subtract 32, then multiply by 5/9: C = (F − 32) × 5/9. For example, (98.6°F − 32) × 5/9 = 37°C.
0°C equals 32°F and 273.15K.
Absolute zero is the coldest possible temperature: −273.15°C, −459.67°F, or 0K. This converter will not accept a value colder than absolute zero, since no such temperature can physically exist.
It's a coincidence of the linear formula: solving C = (C × 9/5 + 32 − 32) × 5/9 for where C equals F gives C = F = −40. It's the one temperature where both scales read the same number.
Kelvin is the absolute thermodynamic temperature scale used in science. It uses the same degree size as Celsius but starts at absolute zero (0K = −273.15°C), so it never goes negative.
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