About TempConvert

TempConvert is a free temperature converter for Celsius, Fahrenheit, Kelvin and Rankine. Every result is computed in your browser from the defining formulas, so the converter is instant and keeps working without a connection once a page has loaded.

How we calculate

Celsius is the hub: K = °C + 273.15, °F = °C × 9/5 + 32, °R = K × 9/5. These are exact by definition of the scales. Results are shown to two decimals by default (you can pick 0 to 3), and the underlying calculation is unit-tested against fixed points such as 0 °C = 32 °F, −40 °C = −40 °F and 0 K = −459.67 °F.

Sources

• Bureau International des Poids et Mesures (BIPM), The International System of Units (SI Brochure): definition of the kelvin and of Celsius temperature.
• NIST, Guide for the Use of the International System of Units (SP 811): Fahrenheit and Rankine conversion factors.
• NHS, "High temperature (fever) in adults" and "Hypothermia"; Mayo Clinic, "Fever: Symptoms and causes": body temperature thresholds.
• UK gas mark convention (225 °F at mark ¼, 250 °F at mark ½, then 25 °F per mark from 275 °F at mark 1), with rounded Celsius as printed by BBC Good Food and Delia Online.
• UK Food Standards Agency and US FDA: fridge and freezer temperatures. IUPAC: standard ambient temperature.
• NASA Lunar Reconnaissance Orbiter (Diviner instrument): lunar surface temperatures.

AI features

The recipe rewriter and the question box use a language model through Vercel AI Gateway, only when you press the button. They are optional; everything else on the site is plain arithmetic.