Fahrenheit to Celsius Converter
Convert Fahrenheit to Celsius — subtract 32, then multiply by 5/9. Results update as you type; exact factors shown.
One degree Fahrenheit is -17.2222 degrees Celsius — see the exact factor, not a rounded rule of thumb.
How the fahrenheit to celsius converter works
Celsius and Fahrenheit are offset scales, so the conversion is not a simple multiplication: °F = °C × 9/5 + 32 and °C = (°F − 32) × 5/9. Kelvin has the same size of degree as Celsius but starts at absolute zero: K = °C + 273.15. The two scales meet at −40°.
Australia is fully metric under the National Measurement Act 1960; imperial units appear only in trade with the US and in older documents.
Common temperature conversions
| From | To | Units |
|---|---|---|
| -40 °F | -40 °C | degrees Fahrenheit to degrees Celsius |
| 0 °F | -17.7778 °C | degrees Fahrenheit to degrees Celsius |
| 32 °F | 0 °C | degrees Fahrenheit to degrees Celsius |
| 50 °F | 10 °C | degrees Fahrenheit to degrees Celsius |
| 68 °F | 20 °C | degrees Fahrenheit to degrees Celsius |
| 72 °F | 22.2222 °C | degrees Fahrenheit to degrees Celsius |
| 80 °F | 26.6667 °C | degrees Fahrenheit to degrees Celsius |
| 90 °F | 32.2222 °C | degrees Fahrenheit to degrees Celsius |
| 98.6 °F | 37 °C | degrees Fahrenheit to degrees Celsius |
| 100 °F | 37.7778 °C | degrees Fahrenheit to degrees Celsius |
| 180 °F | 82.2222 °C | degrees Fahrenheit to degrees Celsius |
| 212 °F | 100 °C | degrees Fahrenheit to degrees Celsius |
Units in this converter and their exact factors
| Unit | Symbol | To kelvin |
|---|---|---|
| degree Celsius | °C | x+273.15 |
| degree Fahrenheit | °F | (x-32)×5÷9+273.15 |
| kelvin | K | x |
FAQFrequently asked questions about temperature conversion
What is the formula?
°C = (°F − 32) × 5/9. Subtract first, or the answer will be wrong.
What is 72°F in Celsius?
22.2°C — a typical thermostat setting.
What is 100°F in Celsius?
37.8°C, just above body temperature.
At what temperature does water boil?
212°F, which is 100°C at sea level.
What is the quick estimate?
Subtract 30 and halve: 70°F → 20°C, close to the true 21.1°C.
Where these figures come from
- BIPM — The International System of Units (SI Brochure, 9th edition) — definitions of the base and derived units.
- NIST Special Publication 811 — Guide for the Use of the International System of Units — the exact conversion factors used here.
- National Measurement Institute (NMI) — Australia's national measurement authority.
Last checked: September 2026. Conversion factors are fixed by definition and do not change with tax years or regulations.