# Degrees Fahrenheit to degrees Celsius converter

> Convert degrees Fahrenheit to degrees Celsius (Fahrenheit to Celsius) with the exact formula, a conversion chart and worked steps.

Interactive version: https://www.calcopenly.com/conversion/fahrenheit-to-celsius
Subject: Unit converters

A Fahrenheit reading often needs conversion for a metric recipe or weather comparison. Subtract the scale's offset before applying the degree-size ratio. An oven's marked setting and its actual measured temperature can differ even when the unit conversion is exact.

Degrees Fahrenheit and degrees Celsius are not related by a single multiplier because the two scales start from different zero points, so the conversion uses a formula. 98.6 °F is 37 °C.

The Celsius and kelvin scales have the same step size; a Fahrenheit degree is 5/9 of a Celsius degree. Absolute zero is 0 K, −273.15 °C or −459.67 °F, and inputs below it are rejected.

## Inputs

- **Degrees Fahrenheit (°F)**

## Results

- Degrees Celsius (°C) — main result
- Conversion
- 1 °C in degrees Fahrenheit (°F)

## Formula

$$
{}^\circ C = ({}^\circ F - 32) \times \tfrac{5}{9}
$$

## Worked examples

### 98.6 °F to °C

- Degrees Fahrenheit (°F): 98.6 °F
- **Degrees Celsius: 37 °C**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

### 60 °F to °C

- Degrees Fahrenheit (°F): 60 °F
- **Degrees Celsius: 15.5555555556 °C**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

### 350 °F to °C

- Degrees Fahrenheit (°F): 350 °F
- **Degrees Celsius: 176.666666667 °C**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

## Questions

### When would I convert Fahrenheit to Celsius?

A Fahrenheit reading often needs conversion for a metric recipe or weather comparison. Subtract the scale's offset before applying the degree-size ratio. An oven's marked setting and its actual measured temperature can differ even when the unit conversion is exact.

### What is the formula to convert Fahrenheit to Celsius?

Subtract 32 and multiply by 5/9: (98.6 °F − 32) × 5/9 = 37 °C.

### Is there a quick way to convert Fahrenheit to Celsius in your head?

Subtract 30 and halve the result. It is exact at 50 °F (10 °C) and gives 20 °C for 70 °F instead of 21.1 °C; the error grows by about 0.5 °C for every 9 °F away from 50.

### At what temperature are Fahrenheit and Celsius equal?

At −40: −40 °F is exactly −40 °C, because solving F = C × 9/5 + 32 with F = C gives C = −40.

### How accurate is the degrees Fahrenheit to degrees Celsius converter?

Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 3 worked examples whose answers come from independent sources; for example, “98.6 °F to °C” is checked against Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions).

### Where does the method come from?

NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B; NIST Handbook 44, Appendix C: General tables of units of measurement; BIPM, The International System of Units (SI Brochure), 9th edition.

## Sources

- [NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B](https://www.nist.gov/pml/special-publication-811)
- [NIST Handbook 44, Appendix C: General tables of units of measurement](https://www.nist.gov/pml/weights-and-measures/publications/nist-handbooks/handbook-44)
- [BIPM, The International System of Units (SI Brochure), 9th edition](https://www.bipm.org/en/publications/si-brochure)