Temperature Converter

The Temperature Converter switches values between Celsius, Fahrenheit, and Kelvin - the three scales you meet in weather reports, ovens, science classes, and engineering specs. Unlike most unit conversions, temperature scales have different zero points, so formulas must both scale and shift.

The conversion passes through Celsius internally. To go from Fahrenheit to Celsius, subtract 32 then multiply by 5/9; the reverse multiplies by 9/5 and adds 32. Kelvin is Celsius shifted by exactly 273.15, with no scaling, so 25 degrees C is 298.15 K. Useful checkpoints: water freezes at 0 C, 32 F, 273.15 K; body temperature is about 37 C or 98.6 F; and water boils at 100 C, 212 F. A handy mental shortcut for weather ranges: F is roughly double C plus 30.

Two notes from practice. Absolute zero - 0 K, about -273.15 C - is the scale floor, so Kelvin values are never negative; if a conversion returns a temperature below that, the input was impossible. And oven temperatures in recipes usually refer to Celsius in Europe and Fahrenheit in the US, so converting a recipe also means converting its oven setting (180 C is about 356 F).

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