Celsius to Fahrenheit Converter
Convert Celsius to Fahrenheit and Fahrenheit to Celsius instantly.
Common Temperature Reference Table
| Celsius (°C) | Fahrenheit (°F) | Description |
|---|---|---|
| -40 | -40 | Celsius and Fahrenheit are equal |
| 0 | 32 | Water freezing point |
| 25 | 77 | Room temperature |
| 30 | 86 | Warm day |
| 37 | 98.6 | Normal human body temperature |
| 40 | 104 | High fever |
| 100 | 212 | Water boiling point |
Celsius and Fahrenheit Conversion Formulas
Converting between Celsius and Fahrenheit relies on two simple linear formulas. Because the two scales have a different zero point and a different size of degree, each conversion involves both a multiplication and an addition (or subtraction).
Celsius to Fahrenheit
°F = °C × 9/5 + 32
Example: 20 °C × 9/5 + 32 = 68 °F
Fahrenheit to Celsius
°C = (°F − 32) × 5/9
Example: (68 °F − 32) × 5/9 = 20 °C
The −40° Crossover Point
There is exactly one temperature at which the Celsius and Fahrenheit scales read the same number: −40°. At this point, −40 °C equals −40 °F. This happens because the two scales are straight lines that cross at a single value. Setting °C equal to °F in the formula gives:
x = x × 9/5 + 32 → x = −40
This makes −40° a handy memory anchor and a quick sanity check when converting very cold temperatures.
Key Reference Temperatures
- Water freezing point: 0 °C = 32 °F. The point at which water turns to ice at standard atmospheric pressure.
- Normal body temperature: 37 °C = 98.6 °F. The accepted average for a healthy adult human.
- Water boiling point: 100 °C = 212 °F. The point at which water turns to steam at sea level.
- The crossover: −40 °C = −40 °F. The only temperature where both scales agree.