Fahrenheit to Celsius

The Fahrenheit and Celsius scales use different zero points and different-sized degree steps, so you cannot convert by simply subtracting or multiplying by one number alone. First, subtract 32 because 32°F is the freezing point of water, which lines up with 0°C, and then multiply by 5/9 because 180 Fahrenheit degrees span the same temperature change as 100 Celsius degrees. That ratio makes each Celsius degree larger than a Fahrenheit degree.

Use this formula when you need to convert weather reports, cooking temperatures, lab measurements, or any temperature written in Fahrenheit into Celsius. It is especially common in science classes and international contexts where Celsius is the standard unit.

• Forgetting to subtract 32 before multiplying
• Using 9/5 instead of 5/9
• Rounding too early and losing accuracy