Fahrenheit to Celsius
Convert Fahrenheit to Celsius instantly. Free temperature converter, no signup.
How to use this tool
- Enter degrees fahrenheit in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your degrees celsius and the full breakdown beneath it.
Convert Fahrenheit to Celsius instantly. Free temperature converter, no signup.
Formula
°C = (°F − 32) × 5/9
Subtract 32 to remove the zero-point offset, then multiply by 5/9 to rescale from Fahrenheit degrees to Celsius degrees.
How it works
To convert Fahrenheit to Celsius, first subtract 32 from the Fahrenheit value, then multiply the result by 5/9 (≈ 0.5556). The subtraction removes the offset between the two scales' zero points (0°C = 32°F), and the 5/9 factor rescales the degree size (each Celsius degree is 1.8× larger than a Fahrenheit degree). Both steps must be applied in the correct order for an accurate result.
Common mistake: Multiplying by 5/9 before subtracting 32, rather than after. Applying the multiplication first produces a completely wrong result — for example, 212°F incorrectly becomes (212 × 5/9) − 32 = 85.8°C instead of the correct 100°C.
Worked example
Convert 212°F (boiling point of water) to Celsius
- Start with the input: 212°F.
- Subtract the zero-point offset: 212 − 32 = 180.
- Multiply by 5/9 to rescale: 180 × 5/9 = 100.
- Result: 100°C — the boiling point of water at sea level.
212°F = 100°C
Common mistakes to avoid
- Multiplying by 5/9 before subtracting 32 instead of subtracting first — 98.6 F calculated as 98.6 x 5/9 - 32 = 22.8 C instead of the correct 37 C.
- Dividing by 1.8 but forgetting to subtract 32, yielding a Fahrenheit-proportional but wrong result.
- Confusing this formula with the reverse (F = C x 9/5 + 32) and accidentally adding 32 instead of subtracting.
Key terms
- Fahrenheit (°F)
- A temperature scale used primarily in the United States, defined so that water freezes at 32°F and boils at 212°F at standard atmospheric pressure.
- Celsius (°C)
- The metric temperature scale where 0°C is the freezing point and 100°C the boiling point of water at standard pressure. Used in science and daily life in most countries.
- Degree Size
- The magnitude of one unit step on a temperature scale. A Celsius degree is exactly 9/5 (1.8) times larger than a Fahrenheit degree, explaining the multiplication factor in conversions.
- Zero-Point Offset
- The difference between the zero points of Celsius and Fahrenheit scales. 0°C equals 32°F, so 32 must be subtracted from Fahrenheit before rescaling to Celsius.
Frequently asked questions
- What is 32 F in Celsius?
- (32 - 32) x 5/9 = 0 C, the freezing point of water.
- How do I quickly estimate Celsius from Fahrenheit in my head?
- Subtract 32, then halve the result (instead of multiplying by 5/9). This underestimates by about 10%, but it is fast — 68 F: (68-32)/2 = 18 C vs the exact 20 C.
- Why is 98.6 F considered normal body temperature?
- 98.6 F is exactly 37 C (37 x 9/5 + 32). The Celsius value was established first; the Fahrenheit equivalent is a rounded conversion.