Celsius
Defined so that water freezes at 0°C and boils at 100°C at standard pressure. It's the everyday scale in nearly every country and the practical scale in science alongside Kelvin.
Temperature conversion
Convert any temperature,
precisely.
Celsius, Fahrenheit, Kelvin and the classical scales — converted instantly.
°C
33.8
°F1 °C = 33.8 °F
Quick to:
1 °C in all units
| Kelvin | 274.15 | K |
| Fahrenheit | 33.8 | °F |
| Rankine | 493.47 | °R |
| Réaumur | 0.8 | °Ré |
About temperature conversion
Temperature scales are not simple multiples of one another — each has its own zero point and step size. Converting between them requires both a multiplication and an offset, which this tool handles automatically.
Fahrenheit
Used primarily in the United States. Water freezes at 32°F and boils at 212°F. Normal human body temperature is about 98.6°F (37°C). The scale's finer degree size makes it slightly more granular for ambient weather.
Kelvin
The SI base unit of thermodynamic temperature. It starts at absolute zero (0 K = −273.15°C) and shares the Celsius degree size, so a 1 K change equals a 1°C change. Used in physics, astronomy and engineering.
Rankine & Réaumur
Rankine (°R) is the Fahrenheit analogue of Kelvin — absolute zero is 0°R. Réaumur (°Ré) once divided water's freezing-to-boiling range into 80 degrees and is now mostly historical, surviving in some European cheese and syrup recipes.
Frequently asked questions
- How do I convert Celsius to Fahrenheit?
- Multiply the Celsius value by 9/5 and add 32. For example, 20°C × 9/5 + 32 = 68°F. The converter handles this instantly with full precision.
- How do I convert Fahrenheit to Celsius?
- Subtract 32 from the Fahrenheit value, then multiply by 5/9. For example, (98.6 − 32) × 5/9 ≈ 37°C — normal human body temperature.
- What is absolute zero?
- Absolute zero is the lowest possible temperature: 0 K, equal to −273.15°C or −459.67°F. At this point all classical molecular motion stops.
- When should I use Kelvin instead of Celsius?
- Kelvin is the SI base unit and is used in science and engineering — especially thermodynamics, astronomy and physics — because it has no negative values and starts at absolute zero.