Fahrenheit to Celsius Converter

Convert °F to °C using C = (F − 32) × 5/9. Temperature conversion is *not* a simple multiplication — the two scales differ in both their zero point and their step size, so an offset is required.

How the formula works

Fahrenheit and Celsius were calibrated against different reference points: Celsius uses 0 °C for water freezing and 100 °C for water boiling at sea level. Fahrenheit puts those points at 32 °F and 212 °F respectively. The 180-degree Fahrenheit span vs. the 100-degree Celsius span produces the 9/5 (= 1.8) ratio, and the freezing-point offset accounts for the +32.

Common temperatures

• Water freezes: 0 °C = 32 °F
• Cool day: 10 °C = 50 °F
• Room temperature: 20 °C ≈ 68 °F
• Body temperature: 37 °C ≈ 98.6 °F
• Hot day: 30 °C = 86 °F
• Water boils (sea level): 100 °C = 212 °F

Quick mental shortcut

Quick estimate: double the °C and add 30 (e.g., 20 °C ≈ 70 °F). The exact formula is °C × 9/5 + 32.

Accuracy note

The formula C = (F − 32) × 5/9 is exact, not an approximation. The reverse formula is F = C × 9/5 + 32. Both Celsius and Fahrenheit are rounded for display in this calculator; underlying math is at full precision.