How to Convert Fahrenheit to Celsius (°F to °C)
Temperature conversions help with American oven recipes in Fahrenheit, weather apps set to the wrong unit, and science homework that uses kelvin. This guide shows how to convert fahrenheit into celsius by hand, with examples and a quick-reference table.
The conversion
Temperature scales have different zero points, so you cannot use a single multiplier. Convert through kelvin: °F converted through kelvin: (((°F-32)*5/9+273.15)-273.15).
°F converted through kelvin: (((°F-32)*5/9+273.15)-273.15)
Worked examples
- 15 °F = -9.4444 °C
- 32 °F = 0 °C
- 100 °F = 37.7778 °C
Fahrenheit to Celsius table
| Fahrenheit | Celsius |
|---|---|
| -40 °F | -40 °C |
| -10 °F | -23.3333 °C |
| 0 °F | -17.7778 °C |
| 10 °F | -12.2222 °C |
| 20 °F | -6.6667 °C |
| 25 °F | -3.8889 °C |
| 30 °F | -1.1111 °C |
| 37 °F | 2.7778 °C |
| 50 °F | 10 °C |
| 100 °F | 37.7778 °C |
| 200 °F | 93.3333 °C |
Common questions
Is °F to °C exact?
The factors used here are the internationally defined values where they exist; results are rounded for display only.
How do I convert back?
Use the Celsius to Fahrenheit converter.
Mistakes to avoid
Forgetting squared and cubed units
Area and volume factors are the length factor squared or cubed, so 1 m² is about 10.76 sq ft, not 3.28.
Rounding the factor too early
Using 3 instead of 3.28 for feet per metre introduces an error of almost 9% before you have started.
Mixing similar-sounding units
US and imperial gallons, pints and tons are different sizes, and decimal kilobytes differ from binary kibibytes.
Background
Singapore adopted the metric system in the 1970s, replacing imperial units and traditional Chinese measures in most official uses. Metric units are now standard in schools, trade and government, but older units survive in property, markets and imported goods.
Unit conversion is simply multiplication by a fixed ratio. The ratio between two units of the same quantity never changes, so once you know it you can convert any value in either direction.
For everyday use, three or four significant figures are usually enough. Engineering, science and trade documents may need more, and rounding should happen only at the end of a calculation.
For any value, use the Fahrenheit to Celsius Converter or browse all temperature converters.
Run your own numbers: Fahrenheit to Celsius Converter