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Temperature Converter

Convert between Celsius, Fahrenheit, and Kelvin, with the formula shown — instantly, in your browser.

Runs in your browser Private & secure Updated August 10, 2026

Convert between Celsius, Fahrenheit, and Kelvin. Enter a value and choose your units below — the result updates instantly, entirely in your browser.

Runs in your browser

Formula

Celsius is used as the pivot for all conversions:

  • Celsius → Fahrenheit: F = C × 9/5 + 32
  • Fahrenheit → Celsius: C = (F − 32) × 5/9
  • Celsius → Kelvin: K = C + 273.15

Worked example: converting 100°C to Fahrenheit: 100 × 9/5 + 32 = 212°F (boiling point of water at sea level).

Inputs below absolute zero (0 K, −273.15°C, −459.67°F) are flagged, since they aren’t physically possible temperatures.

FAQs

Why is Kelvin different from Celsius and Fahrenheit?

Kelvin is an absolute temperature scale starting at absolute zero — the coldest theoretically possible temperature — rather than being anchored to the freezing/boiling points of water like Celsius, or the historical reference points Fahrenheit uses.