Fahrenheit to Celsius
Joining the rest of the world? Convert US Fahrenheit temperatures into the universal language of science and international travel.
Formula: (°C × 9/5) + 32 = °F
Learning the Metric Mindset
If you grew up in the United States, Fahrenheit feels natural. 100 is hot, 0 is cold. But step off a plane almost anywhere else on Earth, and "30 degrees" isn't time for a winter coat—it's a beach day. Our Fahrenheit to Celsius Converter is your bridge to the global standard, helping you understand weather reports, medical charts, and scientific data instantly.
Key Conversions to Memorize
To think in Celsius, you need new anchor points:
The "Tens" Rule
- 10°C (50°F): Cool fall jacket weather.
- 20°C (68°F): Perfect room temperature.
- 30°C (86°F): Hot summer day.
- 40°C (104°F): Heat wave danger.
The Zero Point
In Celsius, 0° is literally the freezing point of water. It makes sense: negative numbers mean ice, positive numbers mean water. In Fahrenheit, water freezes at the arbitrary 32°.
The Subtract-30 Calculation
Need a rough estimate without a phone?
Example for 70°F:
Mental Math: (70 - 30) = 40. Then 40 / 2 = 20°C
Actual Math: 21.1°C.
It's close enough for deciding what to wear!
International Travel
The pilot announces "It's a balmy 23 degrees in London." Don't panic and reach for your parka—that's a lovely 73°F.
Science Class
Every formula in chemistry and physics uses Celsius (or Kelvin). Using 75°F in a gas law equation will get you the wrong answer every time.
Medical Charts
Modern hospitals increasingly use Celsius to avoid errors. A temp of 38.5°C is a significant fever (101.3°F).
Frequently Asked Questions
Who invented these scales?
Daniel Gabriel Fahrenheit (German) proposed his scale in 1724. Anders Celsius (Swedish) proposed his in 1742. Interestingly, Celsius originally defined 0 as boiling and 100 as freezing, but it was reversed after his death.
Does the UK use Fahrenheit?
Mostly no. The UK switched to Celsius decades ago. However, older generations and sometimes tabloid newspapers in summer ("Phew! 90 degrees!") still reference Fahrenheit.
How do exact conversions work?
The formula C = (F - 32) × 5/9 is exact. It accounts for the different start points (32 vs 0) and the different step sizes (1.8 F degrees fit into 1 C degree).
Standard Atmosphere
Boiling points reference standard sea-level pressure. At high altitudes, water boils at lower Celsius temperatures.
Data Privacy
We do not store your calculations. This tool runs entirely in your browser.