Fahrenheit to Celsius Converter

Formula

°C = (°F − 32) × 5/9

Equivalently:

°C = (°F − 32) ÷ 1.8

Reverse:

°F = (°C × 9/5) + 32

Formula variables

• °F — temperature in degrees Fahrenheit.
• °C — equivalent temperature in degrees Celsius.
• 5/9 — the ratio of one Fahrenheit degree to one Celsius degree. One Fahrenheit degree is smaller than one Celsius degree by a factor of 5/9.
• 32 — the offset. Water freezes at 32 °F, which is 0 °C.

Worked Examples

Example 1: Freezing point of water

1. Start: 32 °F.
2. Apply: (32 − 32) × 5/9 = 0 × 5/9.
3. Result: 32 °F = 0 °C.

Example 2: Boiling point of water

1. Start: 212 °F.
2. Apply: (212 − 32) × 5/9 = 180 × 5/9 = 100.
3. Result: 212 °F = 100 °C.

Example 3: Body temperature

1. Start: 98.6 °F.
2. Apply: (98.6 − 32) × 5/9 = 66.6 × 5/9 = 37.
3. Result: 98.6 °F = 37 °C. This is the standard average human core body temperature.

Example 4: Room temperature

1. Start: 68 °F.
2. Apply: (68 − 32) × 5/9 = 36 × 5/9 = 20.
3. Result: 68 °F = 20 °C.

Example 5: −40 intersection

1. Start: −40 °F.
2. Apply: (−40 − 32) × 5/9 = −72 × 5/9 = −40.
3. Result: −40 °F = −40 °C. This is the only temperature where the two scales show the same number.

Common Conversion Chart

Real-World Uses

• Weather: US forecasts use Fahrenheit; most of the world uses Celsius. Converting helps when reading foreign weather data.
• Cooking: Oven temperatures in US recipes are typically in Fahrenheit; European recipes use Celsius. A 350 °F oven is about 177 °C.
• Medicine: Fahrenheit is used for body temperature in the US; Celsius is used almost everywhere else. A fever of 100.4 °F corresponds to 38 °C.
• Science and industry: Celsius (and Kelvin) dominate in scientific contexts, but historical datasets often use Fahrenheit.

Unit Definitions

Fahrenheit (°F)

A temperature scale where 32 °F is the freezing point of water and 212 °F the boiling point at 1 standard atmosphere. Named after Daniel Gabriel Fahrenheit (1686–1736). It is the official scale in the United States and is used informally elsewhere.

Celsius (°C)

A temperature scale where 0 °C is the freezing point of water and 100 °C the boiling point at 1 standard atmosphere. Named after Anders Celsius (1701–1744). Celsius is the SI-accepted derived unit for temperature and is used in almost every country outside the US.

Accuracy and Rounding

Both scales are linearly related, and the conversion is exact. Results are exact in decimal form when the Fahrenheit input has at most one digit after the decimal point (since 5/9 has a recurring decimal but multiplying by (F − 32) and then by 5/9 produces a value that terminates whenever (F − 32) is divisible by 9).

Related Converters

• Celsius to Fahrenheit — the reverse conversion
• Celsius to Kelvin
• Kelvin to Celsius
• All Temperature Converters

Frequently Asked Questions