Convert Celsius, Fahrenheit, and Kelvin with reversible formulas and examples. Fully client-side — no account, uploads, or remote storage.
Added Apr 18, 2026 · Updated May 1, 2026
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Enter a value for temperature to see your result.
Converts a temperature between Celsius, Fahrenheit, and Kelvin simultaneously. Enter a value in any unit and instantly see the equivalent in all three scales.
°F = °C × 9/5 + 32 | K = °C + 273.15
Water boils at 100°C, 212°F, or 373.15 K at standard atmospheric pressure.
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Normal human body temperature is 98.6°F = 37°C.
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Multiply the Celsius value by 9/5 (or 1.8) and then add 32. For example: 20°C × 1.8 + 32 = 68°F.
Absolute zero — the lowest possible temperature — is −273.15°C (−459.67°F or 0 K).
They are linearly related but anchored differently. Scientists and most countries use Celsius for water-centric reference points; the US still commonly uses Fahrenheit for weather and HVAC.
They share the same unit name, but lighting 'Kelvin' describes the hue of a black-body radiator approximation, not the air temperature in your room. Do not mix lighting K with weather conversions.
Yes. Intermediate rounding, float precision, and whether you convert via Kelvin first can shift the last digit. For engineering, carry extra precision until the final display step.