18 °F = -7.8 °C
18 degrees Fahrenheit is -7.777778 degrees Celsius, to six decimal places.
- Precise
- -7.777778 °C
- Rounded
- -7.8 °C
- Formula
- (18 − 32) × 5/9
Convert any other temperature
Type in either box; the other follows, and the scale moves with it. Works for decimals and, for temperatures, numbers below zero.
Around 18 °F
Fahrenheit to Celsius for the whole numbers either side of 18, rounded to one decimal place. Each row opens its own page.
| Degrees Fahrenheit | Degrees Celsius |
|---|---|
| 13 °F | -10.6 °C |
| 14 °F | -10 °C |
| 15 °F | -9.4 °C |
| 16 °F | -8.9 °C |
| 17 °F | -8.3 °C |
| 18 °F | -7.8 °C |
| 19 °F | -7.2 °C |
| 20 °F | -6.7 °C |
| 21 °F | -6.1 °C |
| 22 °F | -5.6 °C |
| 23 °F | -5 °C |
How to convert Fahrenheit to Celsius
The formula
°C = (°F − 32) × 5/9. The two scales start from different zero points, so there is a subtraction as well as a multiplication.
Worked through for 18
Subtract 32: 18 − 32 = -14. Multiply by 5/9: -14 × 5 ÷ 9 = -7.777778. Rounded, that is -7.8 °C.
In your head
Take away 30 and halve it: 70 °F → 40 ÷ 2 = 20 °C (close enough for weather).
Questions
What is 18 °F in Celsius?
18 degrees Fahrenheit is -7.777778 degrees Celsius to six decimal places, or -7.8 °C rounded to one decimal place.
How do you convert degrees Fahrenheit to degrees Celsius?
Use (18 − 32) × 5/9, which gives -7.777778. For a quick estimate: Take away 30 and halve it: 70 °F → 40 ÷ 2 = 20 °C (close enough for weather).
Is 18 °F hot or cold?
18 °F is -7.8 °C: below freezing; water turns to ice.
What is 18 °C in Fahrenheit?
Going the other way, 18 °C is 64.4 °F. The reverse conversion has its own page and converter.
Is the answer exact?
The exact answer has endless decimals, so it is shown to six places (-7.777778). The rounded figure, -7.8, is accurate enough for weather, cooking and thermometers.