Fahrenheit to Celsius (°F to °C) Converter
Your destination's forecast says 25°C, but you think in Fahrenheit — or a US forecast says 77°F and you normally use Celsius. Both describe the same temperature. Convert either way below before choosing what to wear or pack.
77 °F = 25 °C
This is a scale conversion, not a weather forecast or medical assessment. Negative temperatures are supported.
Conversion formula
Celsius = (Fahrenheit − 32) × 5 ÷ 9
Results are rounded to six decimal places; the reference table is rounded to three.
Quick reference
| Fahrenheit (°F) | Celsius (°C) |
|---|---|
| -40 | -40 |
| 32 | 0 |
| 50 | 10 |
| 68 | 20 |
| 77 | 25 |
| 86 | 30 |
| 104 | 40 |
Make a foreign weather forecast easier to read
The United States commonly uses Fahrenheit for weather, while many international forecasts use Celsius. The numbers are not directly comparable: 32°F is 0°C, 68°F is 20°C, and 86°F is 30°C. Check the unit next to the forecast rather than assuming a number alone tells you whether the day will be warm.
Look at the overnight low as well as the daytime high when planning clothing. A warm afternoon does not guarantee a warm evening, especially on an outdoor excursion. Convert both readings and consider rain, wind, humidity, and sun exposure separately. This calculator changes the temperature scale; it does not calculate a heat index or a wind-chill value.
For a quick estimate from Celsius, double the number and add 30. That puts 20°C near 70°F, compared with the exact 68°F. The estimate is useful for a rough impression but not for a reading where precision matters. If converting a thermometer reading for medical care, report the original number, scale, and measurement method to the clinician too.
More conversions
Plan the rest of your trip
Pack for the forecastPlan for European heat without ACUnit definitions: NIST Guide to the SI — conversion factors.