Fahrenheit to Celsius
Fahrenheit to Celsius in Depth
The formula: °C = (°F − 32) × 5/9. The 32 offset exists because Fahrenheit anchored 0° at a brine freezing point — history's most inconvenient zero — while Celsius sensibly anchored at water's freezing point.
Mental Math That Works
Subtract 30, then halve: 68°F → 38 / 2 = 19°C (true: 20°C). Within a degree or two for all weather temperatures — plenty for deciding whether to pack a jacket.
Where It Matters
Understanding US weather as a metric native, converting American cookbook temperatures, and interpreting US medical data (98.6°F = 37°C). Laboratory work always converts to Celsius or Kelvin first.
How to Use the Fahrenheit to Celsius Converter
This converter changes Fahrenheit temperatures into Celsius, the scale used for weather, cooking, and science almost everywhere outside the United States.
- Type a Fahrenheit value, such as a US weather forecast or an oven setting.
- The tool applies the formula °C = (°F − 32) × 5/9.
- Use the Celsius result in your recipe, travel plan, or homework.
Example
Enter 98.6 °F, normal human body temperature, and you get 37 °C. A hot summer day of 86 °F converts to 30 °C, and 32 °F becomes 0 °C, the freezing point of water.
Frequently Asked Questions
Why subtract 32 first?
The two scales start at different points: water freezes at 32 °F but 0 °C. Subtracting 32 aligns the freezing points before the 5/9 ratio rescales the degree size.
Is there a quick mental trick?
For a rough estimate, subtract 30 from the Fahrenheit value and halve the result. So 80 °F becomes about 25 °C, close to the exact 26.7 °C.
Which fields use Celsius?
Nearly all of them: medicine, cooking, weather reporting, and science worldwide. The US, Liberia, and Myanmar are the only countries still using Fahrenheit day to day.