Temperature Converter
Enter a temperature in any common scale and see it in all the others instantly: Celsius (°C), Fahrenheit (°F), Kelvin (K), Rankine (°R) and Réaumur (°Ré). The value is converted to Kelvin internally and then to every scale, so conversions are exact — unlike simple multiplication, temperature scales have different zero points, which this handles correctly. Handy for cooking and weather (°C ↔ °F), science and engineering (Kelvin, Rankine) and history (Réaumur). Negative values and values below absolute zero are accepted as entered. Everything is computed locally in your browser.
°C (Celsius)
100
°F (Fahrenheit)
212
K (Kelvin)
373.15
°R (Rankine)
671.67
°Ré (Réaumur)
80
How to use
- Type a temperature value.
- Pick the scale you entered it in.
- Read the value in every other scale and copy whichever you need.
Frequently asked questions
- How do Celsius and Fahrenheit relate?
- °F = °C × 9/5 + 32, and °C = (°F − 32) × 5/9. They cross at −40°, where −40°C equals −40°F. Water freezes at 0°C / 32°F and boils at 100°C / 212°F.
- What is Kelvin?
- Kelvin is the SI base unit of temperature. It starts at absolute zero (0 K = −273.15°C) and shares the same degree size as Celsius, so K = °C + 273.15.
- What are Rankine and Réaumur?
- Rankine (°R) is an absolute scale with Fahrenheit-sized degrees (0 K = 0°R), used in some engineering fields. Réaumur (°Ré) sets water's freezing point at 0 and boiling at 80, and appears in older texts and some cheese and syrup recipes.
- Can I enter values below absolute zero?
- The tool converts whatever number you type, so it won't stop you — but physically nothing can be colder than absolute zero (−273.15°C / 0 K), so negative Kelvin results have no real-world meaning.
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