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Convert Fahrenheit (°F) to Celsius (°C)

Category: Temperature

-17.222222 celsius

1 fahrenheit = -17.222222 celsius

Precision: 6 decimals; very small non-zero results use significant digits.

How to convert Fahrenheit to Celsius

Temperature scales combine ratios and offsets. Kelvin is absolute (no negative values), Celsius offsets Kelvin by 273.15, and Fahrenheit uses a different step and zero point. Because offsets exist, temperature conversions require both a factor and an addition/subtraction.

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Quick conversion table

Handy values for Fahrenheit (°F) to Celsius (°C). Click a value to calculate that result.

Fahrenheit (°F) Celsius (°C)
-17.222222
-17.5
-16.388889
-12.222222

Fahrenheit to Celsius formula

Subtract 32 from Fahrenheit, then multiply by 5/9.

Formula: °C = (°F − 32) × 5/9

Example

68 °F: (68 − 32) × 5/9 = 20 °C

A change of 1 °C equals a change of 1.8 °F.

Conversion formula

Use the following formula:

°C = (°F − 32) × 5/9

Temperature conversions use exact affine formulas (ratio + offset).

Common mistakes

  • Using only a ratio (×1.8 or ×0.555…) without adding/subtracting the offset (±32, +273.15).
  • Rounding too early; convert first, then round to the desired precision.

Unit facts

  • Fahrenheit (°F): Fahrenheit (°F) is an offset scale: 32 °F freezing, 212 °F boiling of water (1 atm).
  • Celsius (°C): Celsius (°C) is an offset scale: 0 °C at water’s freezing point, 100 °C at boiling (1 atm).

About Fahrenheit (°F)

Fahrenheit (°F)

Offset scale with 32 °F as water’s freezing point and 212 °F as boiling at 1 atm. Offers finer granularity per degree for everyday weather reporting in the US.

History: Proposed by Daniel G. Fahrenheit in the 18th century; based on calibration points available at the time.

About Celsius (°C)

Celsius (°C)

Offset scale with 0 °C at water’s freezing point and 100 °C at boiling (at 1 atm). Converts to Kelvin by adding 273.15. Widely used in daily weather and science.

History: Named for Anders Celsius (1740s). Redefined through absolute thermodynamic scales as metrology advanced.

Frequently asked questions

How do I convert Fahrenheit (°F) to Celsius (°C)?
Enter the temperature in Fahrenheit (°F) and the calculator will apply the exact conversion formula to return the result in Celsius (°C).
Is Fahrenheit (°F) to Celsius (°C) conversion exact?
Yes. Temperature conversions use exact affine formulas with a ratio and an offset.
Why does temperature conversion depend on the input value?
Unlike linear unit conversions, temperature scales do not start at the same zero point, so the conversion includes an offset.

Convert Fahrenheit (°F) to other units

Convert other units to Celsius (°C)