Convert Celsius to Fahrenheit
Fahrenheit = Celsius × 1.8 + 32. Type any temperature below to convert celsius to fahrenheit both ways — it runs entirely in your browser.
Celsius to Fahrenheit formula
Temperature scales have different zero points, so the conversion is a multiply-and-add, not a single ratio:
Fahrenheit = Celsius × 1.8 + 32
To go the other way, Celsius = Fahrenheit × 0.5555556 − 17.77778.
Worked example
Convert 25 °C to fahrenheit:
= 25 × 1.8 + 32 = 77 °F.
Common temperatures in Celsius and Fahrenheit
| Reference point | Celsius (°C) | Fahrenheit (°F) |
|---|---|---|
| Absolute zero | -273.15 | -459.67 |
| Freezing point of water | 0 | 32 |
| Refrigerator | 4 | 39.2 |
| Room temperature | 21 | 69.8 |
| Normal human body temperature | 37 | 98.6 |
| A hot summer day | 45 | 113 |
| Boiling point of water (sea level) | 100 | 212 |
About the Celsius and Fahrenheit scales
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.
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.
Frequently asked questions
- What is 25 °C in Fahrenheit?
- 25 °C = 77 °F.
- How do I convert Celsius to Fahrenheit?
- Use fahrenheit = celsius × 1.8 + 32. For example, 25 °C → 77 °F.
- How do I convert Fahrenheit back to Celsius?
- Reverse it: celsius = fahrenheit × 0.5555556 − 17.77778.
- Why isn't converting Celsius to Fahrenheit just multiplication?
- Because the two scales start their zero at different temperatures, so after scaling by 1.8 you also add 32. Skipping that constant is the most common temperature-conversion mistake.