Fahrenheit to Celsius
Convert any value from fahrenheit to celsius with full precision. Use the converter above for instant results, or read on for the exact formula, worked examples, common uses, and answers to frequently asked questions.
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About the Fahrenheit to Celsius conversion
Temperature is one of the few common measurements where you cannot simply multiply by a conversion factor. Unlike length and weight, temperature scales have different zero points, so you need to apply an offset in addition to scaling. This converter handles the math for Celsius, Fahrenheit, Kelvin, Rankine, Réaumur, and the less common Delisle and Newton scales.
This page focuses specifically on converting fahrenheit to celsius. Use the converter above for instant results, or read on for what each unit is, the exact formula, a worked example, and answers to common questions.
Understanding fahrenheit and celsius
What is a fahrenheit?
The Fahrenheit scale places the freezing point of water at 32 degrees and its boiling point at 212 degrees. It is the everyday temperature scale in the United States for weather, cooking, and body temperature.
What is a celsius?
The Celsius scale sets zero at the freezing point of water and 100 at its boiling point at standard pressure, and it is defined in modern terms relative to absolute zero and the triple point of water. It is the everyday temperature scale in most of the world for weather, cooking, and science.
Temperature formulas
Unlike most conversions, temperature scales have different zero points, so conversion uses both multiplication and an offset.
- Celsius → Fahrenheit: °F = (°C × 9/5) + 32
- Fahrenheit → Celsius: °C = (°F − 32) × 5/9
- Celsius → Kelvin: K = °C + 273.15
- Kelvin → Celsius: °C = K − 273.15
- Fahrenheit → Rankine: °R = °F + 459.67
- Celsius → Rankine: °R = (°C + 273.15) × 9/5
Sources and accuracy
The modern Celsius scale is defined using the triple point of water (0.01 °C) and absolute zero (−273.15 °C), as established by the BIPM and NIST. The Fahrenheit scale was originally defined using a brine solution and later standardized at 32 °F for the freezing point and 212 °F for the boiling point of water.
Conversion factors are cross-checked against the NIST SP 811 guide, the BIPM SI brochure, and ISO 80000, plus published historical references for older unit systems. For mission-critical work such as medical dosing, legal-for-trade measurement, aerospace, or large-scale engineering, always verify independently with the original source.
Practical tips
When converting temperature differences (not single temperatures), remember that 1 °C = 1.8 °F = 1 K = 1.8 °R. Many people forget the offset when converting weather or oven temperatures — enter the actual temperature (not a difference) above.
Frequently asked questions
How accurate is this fahrenheit to celsius converter?
It uses the official international conversion factors from NIST and BIPM with full double-precision floating-point accuracy. For everyday use the result is precise to many more decimal places than any practical measurement requires.
Can I convert celsius back to fahrenheit as well?
Yes. Use the swap button above to reverse the From and To fields, or change either dropdown to any unit in the temperature category. The calculation runs entirely in your browser, so it also works offline once the page has loaded.