-18 Celsius to Fahrenheit
-18°C = -0.4°F
-18 degrees Celsius is equal to -0.4 degrees Fahrenheit.
Convert -18 Celsius to Fahrenheit using our free temperature converter.
How to convert -18 °C to °F
Use the formula °F = (°C × 9/5) + 32 and substitute -18 for °C:
°F = (-18 × 9/5) + 32°F = -32.4 + 32°F = -0.4
So -18 °C = -0.4 °F.
What does -18 °C mean?
Home freezers are typically set to about −18 °C, which is the familiar 0 °F setting recommended for long-term frozen food storage.
-18 °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.
- Fahrenheit
- -0.4 °F
- Kelvin
- 255.15 K
- Quick estimate (double + 30)
- -6 °F
For -18 °C the quick “double it and add 30” estimate gives -6 °F — 5.6 °F too low. The shortcut works best between about 0 °C and 20 °C; use the exact formula for anything that matters.
More in this range: Below freezing.
-18 °C and nearby values
Related conversions
The Celsius to Fahrenheit formula
°F = (°C × 9/5) + 32
Multiply the Celsius temperature by 9/5 (1.8) because a Celsius degree is 1.8 times larger than a Fahrenheit degree, then add 32 because water freezes at 32 °F rather than 0 °F. To go the other way, use °C = (°F − 32) × 5/9 — for example, -0.4 °F back to Celsius gives -18 °C.
See the formula explained in detail or the step-by-step conversion guide.
Frequently asked questions
What is -18 Celsius in Fahrenheit?
-18 degrees Celsius is equal to -0.4 degrees Fahrenheit (-18 °C = -0.4 °F).
How do you convert -18 °C to °F?
Multiply -18 by 9/5 (or 1.8) and add 32: (-18 × 1.8) + 32 = -0.4 °F.
Is -18 °C hot or cold?
It is very cold — well below freezing. -18 °C is -0.4 °F.
What is -18 °C in Kelvin?
Add 273.15 to the Celsius value: -18 °C = 255.15 K.