Temperature Converter
Formula
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How the temperature converter works
Enter a temperature, pick from and to units, and get an instant answer — plus the value in all five scales (Celsius, Fahrenheit, Kelvin, Rankine, Réaumur) in one table. Use the swap button to flip direction, and set decimal places to taste.
The formulas
°F = °C × 9/5 + 32 and K = °C + 273.15 are the two you'll use most. Everything converts through Celsius internally, so no rounding drift between pairs.
Frequently asked questions
Why are there so many temperature scales?
Celsius (metric, water-based) and Fahrenheit (US daily life) cover almost everything. Kelvin is for science — it starts at absolute zero. Rankine and Réaumur are historical but still asked about in exams.
What is absolute zero?
−273.15°C (−459.67°F, 0 K) — the coldest anything can theoretically get, where molecular motion stops. That's why Kelvin has no negative values.
Is 1°C the same size as 1°F?
No — a Celsius degree is 9/5 the size of a Fahrenheit degree. But a 1°C step equals a 1 K step exactly; they just start at different zeros.
How do I convert body temperature 98.6°F?
Type 98.6, from Fahrenheit to Celsius: (98.6 − 32) × 5/9 = 37°C. Try it above.