Temperature Converter
Convert instantly between different units.
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Temperature Conversion Formulas
Temperature scales were developed independently and use different zero points and interval sizes. Understanding the conversion formulas helps you convert mentally when no calculator is available.
- °C to °F: (°C × 9/5) + 32
- °F to °C: (°F − 32) × 5/9
- °C to K: °C + 273.15
- K to °C: K − 273.15
- °F to K: (°F − 32) × 5/9 + 273.15
Common Reference Points
- Water freezes: 0°C / 32°F / 273.15 K
- Body temperature: 37°C / 98.6°F / 310 K
- Water boils: 100°C / 212°F / 373.15 K
- Absolute zero: −273.15°C / −459.67°F / 0 K
- Room temperature: ~20–22°C / 68–72°F
Why does the US use Fahrenheit instead of Celsius?
The U.S. adopted Fahrenheit in the 1700s and never transitioned to Celsius during the metric system shift (unlike most of the world). The Fahrenheit scale was calibrated to human-relevant temperatures — 0°F was the coldest temperature Daniel Fahrenheit could produce in his lab, and 100°F was close to body temperature. The U.S., Liberia, and the Cayman Islands are the primary countries still using Fahrenheit officially.
What is Kelvin used for?
Kelvin is the SI base unit of temperature and is used in scientific and engineering contexts where absolute temperature matters — thermodynamics, astrophysics, cryogenics, and gas law calculations. Unlike Celsius and Fahrenheit, Kelvin starts at absolute zero (the point where all molecular motion stops), making it essential for equations involving ratios of temperatures.