Subtract 32, then multiply by 5/9: C = (F - 32) x 5/9. For example, 68 F minus 32 is 36, and 36 x 5/9 = 20 C. A free converter applies the formula instantly for any temperature.
Free Fahrenheit to Celsius converter. Convert F to C instantly using the correct formula (C = (F - 32) x 5/9). Live result as you type, private.
Open Fahrenheit to Celsius Converter → Free toolFree temperature converter. Convert between Celsius, Fahrenheit, and Kelvin instantly with correct offset formulas, updating live as you type a value.
Open Temperature Converter →The two scales put freezing water at different numbers (32 F vs 0 C), which is the minus 32. Between freezing and boiling there are 180 Fahrenheit degrees but only 100 Celsius degrees, so each Fahrenheit degree is 5/9 of a Celsius degree, which is the multiplier. Put together: C = (F - 32) x 5/9.
32 F is 0 C (freezing), 50 F is 10 C, 68 F is 20 C (room temperature), 98.6 F is 37 C (the traditional body temperature figure) and 212 F is 100 C (boiling). For everything in between, the converter gives the exact value as you type.
Exactly 37 C: 98.6 minus 32 is 66.6, and 66.6 x 5/9 = 37.
Subtract 30 and halve the result. For 68 F that gives 19, close to the true 20 C. It is rough but fine for weather.
At minus 40. The value -40 F equals -40 C, the one point where the scales cross.