Convert Fahrenheit to Celsius easily.

Whether you're checking a fever, following an international recipe, or analyzing climate data, converting between Fahrenheit and Celsius remains one of the most practical math skills. These two temperature scales divide continents more than oceans, with Americans clinging to Fahrenheit while most others use Celsius. But here's the twist: understanding both systems makes you weather-bilingual, ready to interpret any forecast or oven manual.

Unit definitions

What is a Fahrenheit (°F)?

Developed by Daniel Fahrenheit in 1724, this scale originally used freezing brine (0°F) and human body temperature (96°F) as fixed points. Today, it defines water's freezing point at 32°F and boiling point at 212°F. The Fahrenheit degree is 5/9 the size of a Celsius degree. You'll see it used primarily in the United States for weather reports, cooking temperatures, and household thermostats.

Symbol: °F
Common uses: US weather forecasts, oven settings, pool temperatures
Definition: (Celsius × 9/5) + 32

What is a Celsius (°C)?

Created by Anders Celsius in 1742, this metric system unit sets water's freezing point at 0°C and boiling point at 100°C (at sea level). Most countries use it for daily temperature measurements and scientific reporting. Interestingly, Celsius originally proposed 0° for boiling and 100° for freezing, but the scale was reversed after his death.

Symbol: °C
Common uses: Global weather reporting, scientific research, medical measurements
Definition: (Fahrenheit - 32) × 5/9

Conversion formula

The mathematical bridge between these scales is straightforward once you understand its components. To convert Fahrenheit to Celsius:

°C = (°F - 32) × 5/9

Breaking it down:

1. Subtract 32 to account for Fahrenheit's higher zero point
2. Multiply by 5/9 to adjust for the smaller degree size

For Celsius to Fahrenheit: °F = (°C × 9/5) + 32

Example calculations

Let's practice with two common temperatures:

1. 32°F to °C
   (32 - 32) × 5/9 = 0 × 5/9 = 0°C
   That's why 32°F marks water's freezing point
2. 98.6°F (body temp) to °C
   (98.6 - 32) = 66.6
   66.6 × 5/9 ≈ 37°C
   Turns out "normal" body temperature actually averages closer to 97.7-99.5°F (36.5-37.5°C) in real life

Conversion tables

Fahrenheit to Celsius

Celsius to Fahrenheit

From thermometers to smartphones: A temperature tale

The Fahrenheit Celsius rivalry began with competing 18th century instruments. Fahrenheit's mercury thermometers offered unprecedented precision, which helped his scale gain initial popularity. Celsius's water-based system eventually won over scientists due to its decimal simplicity. By the 1940 s, most nations had switched to Celsius, though the US held onto Fahrenheit partly due to the cost of changing infrastructure.

An interesting benefit of Fahrenheit: its 0-100 range approximately covers outdoor temperatures experienced in temperate climates. This made it intuitive for weather reporting before digital displays. Celsius proponents argue their scale better aligns with the metric system's base-10 logic.

Interesting facts

1. The original Fahrenheit scale had three fixed points: 0° (freezing brine), 32° (water ice), and 96° (human body temp)
2. NASA uses both scales: Fahrenheit for public communications, Celsius/Kelvin for engineering
3. Digital cooking appliances often display both units simultaneously
4. -40°F/C isn't just a math trick: it's colder than Antarctica's average winter temp
5. Some medical studies use Fahrenheit for patient comfort in the US, Celsius elsewhere

FAQ