Fahrenheit to Celsius Converter
Turn Fahrenheit into Celsius for cooking temperatures, forecasts, and quick international conversion.
How to use this Fahrenheit to Celsius converter
- Enter Fahrenheit
Type the temperature into the Fahrenheit field.
- Read the result
The equivalent value in Celsius appears instantly.
- Double-check with the shortcut
For a rough estimate, subtract 30 and halve the result.
How this Fahrenheit to Celsius converter works
This converter translates Fahrenheit into Celsius using the exact reverse linear formula. It is useful for international recipes, scientific references, and understanding weather temperatures reported in a different system.
°C = (°F − 32) × 5/9 (68 − 32) × 5/9 = 20 °C.
A fever thermometer reads 101 °F. In Celsius: (101 − 32) × 5/9 = 38.33 °C — above the 37 °C normal baseline.
- ✓ All three conversions are exact linear transformations — no rounding or approximation is applied to the formulas themselves.
- ✓ Kelvin values below 0 are physically impossible (absolute zero is 0 K = −273.15 °C); the calculator will still compute them but they have no physical meaning.
- ✓ The Celsius scale used here is the modern definition tied to the kelvin via the 2019 SI redefinition, where one degree Celsius equals exactly one kelvin.
- ✓ Results are displayed rounded to two decimal places; internal arithmetic uses full floating-point precision.
- The formula °F = °C × 9/5 + 32 is exact by definition — memorizing it and the inverse covers the vast majority of everyday temperature conversions.
- At −40°, Celsius and Fahrenheit intersect: −40 °C = −40 °F. This is a useful mental anchor for checking your conversions.
- Kelvin is the SI base unit for thermodynamic temperature and is used in scientific contexts where ratios matter (e.g. gas laws, blackbody radiation). It has no degree symbol.
- For cooking and weather, Celsius-to-Fahrenheit is the most common conversion; for physics and chemistry, Celsius-to-Kelvin dominates.
- National Institute of Standards and Technology (NIST) — Guide for the Use of the International System of Units
- Bureau International des Poids et Mesures (BIPM) — The International System of Units (SI), 9th edition, 2019
Fahrenheit to Celsius in practice
This conversion is especially common when reading recipes from other regions, interpreting weather forecasts while travelling, or understanding medical temperature thresholds. Normal body temperature is about 98.6 °F (37 °C), water freezes at 32 °F (0 °C), and a hot summer day of 100 °F translates to about 37.8 °C. The formula subtracts 32 first to remove the offset between the two zero points, then multiplies by 5/9 to scale from the smaller Fahrenheit degree to the larger Celsius degree. For quick mental math, subtract 30 and halve the result — close enough for everyday estimates.
Fahrenheit to Celsius converter FAQs
What is 32 °F in Celsius?
32 °F equals 0 °C, the freezing point of water.
Is there a quick way to estimate Fahrenheit to Celsius?
Subtract 30 and then halve the result. For example, 90 °F becomes (90 − 30) ÷ 2 = 30 °C. The exact answer is about 32.2 °C, so the shortcut gives a useful ballpark.
At what temperature are Fahrenheit and Celsius equal?
The two scales cross at −40°. Both −40 °F and −40 °C represent the same temperature.