Instant, two-way conversion across common engineering units.
1 °F = -17.222222 °C(Fahrenheit → Celsius)
To convert Fahrenheit to Celsius, subtract 32 from the value, then multiply by 5/9. Temperature scales use offsets as well as ratios, so a conversion formula is applied rather than a single multiplier.
Temperature scales have different zero points, so the values are matched at the same physical temperature rather than compared by size.
Fahrenheit (°F) is the temperature scale used in the United States.
Celsius (°C) is the everyday temperature scale used in most of the world and in building physics.
To convert Fahrenheit to Celsius, subtract 32 from the value, then multiply by 5/9. For example, 20 °F equals -6.6666667 °C.
Reverse the formula: multiply the value by 9/5 and add 32. The converter above works in both directions, so you can type into either field.
Celsius and Fahrenheit have different zero points, so a simple multiplier cannot work. Each conversion applies both a scale factor and an offset.
Water freezes at 0 °C or 32 °F and boils at 100 °C or 212 °F, so one Celsius degree covers 1.8 Fahrenheit degrees. The scales cross at -40.
Kelvin is the SI unit and starts at absolute zero, so it is used for thermal calculations, U-values and any scientific reporting. Temperature differences are identical in kelvin and Celsius.
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