-18 Fahrenheit to Celsius
-18 °F ≈ -27.78 °C
-18 degrees Fahrenheit is approximately -27.78 degrees Celsius.
How to convert -18 °F to °C
Use the formula °C = (°F − 32) × 5/9:
°C = (-18 − 32) × 5/9°C = -50 × 5/9°C = -27.777778
So -18 °F = -27.777778 °C, or about -27.78 °C rounded.
Rounded values and quick estimate
- Rounded to a whole number: -28 °C
- Rounded to one decimal place: -27.8 °C
Quick mental estimate: subtract 30 and halve it. For -18 °F that gives about -24 °C — off by 3.78 °C (13.6%). Use the exact formula when precision matters.
-18 Fahrenheit in other units
-27.78 °C is very cold weather, well below the freezing point of water. It is typical of a hard winter in northern climates; warm layers, gloves and a hat are essential outdoors.
- Celsius
- -27.78 °C
- Degrees Réaumur
- -22.22 °Ré
- Degrees Delisle
- 191.67 °De
- Degrees Newton
- -9.17 °N
- Degrees Rømer
- -7.08 °Rø
- Kelvin
- 245.37 K
- Rankine
- 441.67 °R
-18 °F and nearby values
About fahrenheit and celsius
The Fahrenheit scale puts water’s freezing point at 32 °F and boiling point at 212 °F. It is the everyday temperature scale in the United States.
The Celsius scale sets the freezing point of water at 0 °C and its boiling point at 100 °C (at sea level). It is used for everyday temperatures in almost every country.
Related conversions
Frequently asked questions
What is -18 Fahrenheit in Celsius?
-18 degrees Fahrenheit is about -27.78 degrees Celsius (-18 °F ≈ -27.78 °C).
How do you convert -18 °F to °C?
Apply °C = (°F − 32) × 5/9: °C = (-18 − 32) × 5/9, °C = -50 × 5/9, °C = -27.777778.
How many degrees Fahrenheit is -27.78 °C?
-27.78 °C is about -18 degrees Fahrenheit.