Temperature Converter

Temperature is the one unit category where a simple multiplier isn't enough to convert correctly, which is exactly why so many quick conversions people do in their head come out wrong. Length or weight units all share a zero point — zero meters is the same "nothing" as zero feet — but Celsius, Fahrenheit, and Kelvin don't: 0°C is 32°F, not 0°F, because the two scales' zero points sit in different places. This converter handles that properly with real conversion formulas for each scale rather than an approximate ratio, and includes every temperature scale that's seen genuine historical or scientific use — not just the three everyone knows, but Rankine (used in some engineering contexts), Réaumur, Newton, Rømer, and Delisle, each with its own distinct zero point and step size.

Type a value into either field and the other converts instantly; swap reverses which scale is which. The math has been checked against known fixed points — 0°C correctly converts to 32°F and 273.15 K here, 100°C to 212°F, and −40 is the one temperature where Celsius and Fahrenheit genuinely agree, which the converter confirms rather than rounds toward.

Dedicated single-pair pages for Celsius↔Fahrenheit, Celsius↔Kelvin, and Fahrenheit↔Kelvin are linked below, each with a reference table built around genuinely useful values — freezing, body temperature, boiling — rather than arbitrary round numbers. Everything computes locally in your browser with no external service involved.