Why can't temperature be converted with a single multiplier?

Because the scales start at different points. Length units all share a zero — zero metres is zero feet — but zero Celsius is 32 Fahrenheit, so every conversion needs an offset as well as a ratio.

An absolute scale like Kelvin but using Fahrenheit-sized degrees, so absolute zero is 0°R and water freezes at 491.67°R. It still appears in some US engineering and thermodynamics work.

Temperature Converter

Convert between all four temperature scales. Temperature is the one conversion you can't do with a simple multiplier, because the scales don't share a zero point — 0°C is 32°F, not 0°F — so each conversion applies the correct offset as well as the ratio.

Value

From

100 °Celsius =

212 °Fahrenheit

°Celsius: 100
Kelvin: 373.15
°Rankine: 671.67

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Why use this tool

Celsius, Fahrenheit, Kelvin and Rankine
Handles the offset between scales properly, not just the ratio
All four scales shown for every value
Works below zero and below absolute zero without breaking

How it works

1Enter the temperature.
2Choose the scale you're converting from and to.
3Read the answer, with all four scales listed underneath.

Temperature Converter — frequently asked questions

Multiply by 9/5 and add 32. So 20°C × 1.8 = 36, plus 32 = 68°F. The rough mental version is double it and add 30, which gets you within a couple of degrees.

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