Fahrenheit to Celsius Converter

Fahrenheit to Celsius — quick reference

The formula

Going from Fahrenheit to Celsius means undoing the °C→°F formula: subtract the 32-degree offset first, then scale by 5/9:

°C = (°F − 32) × 5/9

Worked example with the default: (98.6 − 32) × 5/9 = 66.6 × 5/9 = 37.0 °C — normal body temperature.

Anchor points to sanity-check any answer: 32 °F = 0 °C (freezing), 212 °F = 100 °C (boiling at sea level), and −40 °F = −40 °C, the single temperature that reads the same on both scales.

How to use the fahrenheit to celsius converter

This is the conversion for taking a Fahrenheit temperature and reading it in Celsius — checking a fever against guidance written in metric, converting a US recipe for a metric oven, or telling someone abroad what the weather actually is back home. Enter Fahrenheit, read Celsius; Swap reverses it.

The medical case is the one where precision counts. Normal body temperature is 98.6 °F, which is 37.0 °C, and a fever threshold of 100.4 °F is exactly 38.0 °C — the number most international health guidance uses. A degree of Fahrenheit is smaller than a degree of Celsius, so small-looking changes matter: 102 °F is 38.9 °C, not far off the 39 °C that often prompts a call to a doctor.

Recipes run the other way from the usual problem: a US recipe gives the oven in Fahrenheit and your oven is marked in Celsius. A 350 °F bake is 176.7 °C — round to the nearest 5 and set 175 °C; a 425 °F roast is 218 °C, so set 220. Convert first, then snap to your oven’s marks.

The mental shortcut is “subtract 30, then halve” — for 68 °F, 38 halved is 19 °C, against the true 20. It’s close for weather and quick checks but loses accuracy as temperatures climb, so use the exact formula for fevers, candy and meat thermometers, and anything where a degree or two changes the decision.

Frequently asked questions