Celsius to Fahrenheit: Formula & Conversion Guide
Celsius and Fahrenheit are the two temperature scales you meet most — Celsius almost everywhere, Fahrenheit mainly in the US. Converting between them takes one small formula. This guide shows it both ways, with examples and a reference table, plus a converter for instant answers.
The Celsius to Fahrenheit formula
To convert Celsius to Fahrenheit: °F = (°C × 9 ÷ 5) + 32.
Example: 20 °C = (20 × 9 ÷ 5) + 32 = 36 + 32 = 68 °F. A comfortable room temperature of 20–22 °C is about 68–72 °F.
Fahrenheit back to Celsius
Going the other way: °C = (°F − 32) × 5 ÷ 9.
Example: 98.6 °F (body temperature) = (98.6 − 32) × 5 ÷ 9 = 37 °C. The Temperature Converter does both directions as you type.
Quick reference table
- 0 °C = 32 °F — water freezes
- 37 °C = 98.6 °F — body temperature
- 100 °C = 212 °F — water boils
- −40 °C = −40 °F — the two scales meet here
A fast mental shortcut
For a rough estimate, double the Celsius value and add 30: 20 °C → about 70 °F. It is not exact (the real answer is 68 °F) but it is close enough for weather. For precise results, use the formula or the converter.
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Last updated: July 6, 2026