Temperature Converter
Convert between Celsius, Fahrenheit, Kelvin, and Rankine instantly.
Temperature Quick Reference
| Description | °C | °F | K |
|---|---|---|---|
| Absolute zero | −273.15 | −459.67 | 0 |
| Water freezes | 0 | 32 | 273.15 |
| Room temperature | 20–22 | 68–72 | 293–295 |
| Body temperature | 37 | 98.6 | 310.15 |
| Water boils | 100 | 212 | 373.15 |
| Oven (medium heat) | 180 | 356 | 453 |
| C° = F° crossover | −40 | −40 | 233.15 |
Frequently Asked Questions
What is the formula to convert Celsius to Fahrenheit?
°F = (°C × 9/5) + 32. For example, 100°C = (100 × 1.8) + 32 = 212°F. To go the other way: °C = (°F − 32) × 5/9.
What is absolute zero?
Absolute zero is the lowest theoretically possible temperature, at which point molecules have minimal thermal motion. It is 0 K (Kelvin), which equals −273.15°C or −459.67°F. Nothing in the universe can reach absolute zero, though experiments have come within billionths of a degree.
When would I use Kelvin?
Kelvin is used in science and engineering because it starts at absolute zero, making many thermodynamic equations simpler. Gas laws (Boyle's Law, Charles's Law) require temperatures in Kelvin. It is the SI base unit of temperature.
What is the Rankine scale?
The Rankine scale is the imperial counterpart to Kelvin — it starts at absolute zero but uses Fahrenheit-sized degrees. 0 R = 0 K = −459.67°F. Rankine is used in some US engineering thermodynamics contexts.
At what temperature are Celsius and Fahrenheit equal?
Celsius and Fahrenheit are equal at −40°. This is a useful fact to remember: −40°C = −40°F. Below −40°, Fahrenheit numbers are higher; above −40°, Celsius numbers are higher than the equivalent Fahrenheit.