Convert Fahrenheit to Celsius
Celsius = Fahrenheit × 0.5555556 − 17.77778. Type any temperature below to convert fahrenheit to celsius both ways — it runs entirely in your browser.
Fahrenheit to Celsius formula
Temperature scales have different zero points, so the conversion is a multiply-and-add, not a single ratio:
Celsius = Fahrenheit × 0.5555556 − 17.77778
To go the other way, Fahrenheit = Celsius × 1.8 + 32.
Worked example
Convert 98.6 °F to celsius:
= 98.6 × 0.5555556 − 17.77778 = 37 °C.
Common temperatures in Fahrenheit and Celsius
| Reference point | Fahrenheit (°F) | Celsius (°C) |
|---|---|---|
| Absolute zero | -459.67 | -273.15 |
| Freezing point of water | 32 | 0 |
| Refrigerator | 39.2 | 4 |
| Room temperature | 69.8 | 21 |
| Normal human body temperature | 98.6 | 37 |
| A hot summer day | 113 | 45 |
| Boiling point of water (sea level) | 212 | 100 |
About the Fahrenheit and Celsius scales
Fahrenheit: Fahrenheit puts water’s freezing point at 32° and its boiling point at 212° — a 180-degree span. It is the everyday scale in the United States and a few other territories.
Celsius: Celsius (centigrade) puts 0° at the freezing point of water and 100° at its boiling point at sea level. It is the everyday temperature scale used almost everywhere outside the United States.
Frequently asked questions
- What is 98.6 °F in Celsius?
- 98.6 °F = 37 °C.
- How do I convert Fahrenheit to Celsius?
- Use celsius = fahrenheit × 0.5555556 − 17.77778. For example, 98.6 °F → 37 °C.
- How do I convert Celsius back to Fahrenheit?
- Reverse it: fahrenheit = celsius × 1.8 + 32.
- Why isn't converting Fahrenheit to Celsius just multiplication?
- Because the two scales start their zero at different temperatures, so after scaling by 0.5555556 you also subtract 17.77778. Skipping that constant is the most common temperature-conversion mistake.