Fahrenheit to Celsius Converter
Convert temperatures between Fahrenheit, Celsius, and Kelvin instantly. See the formula, step-by-step math, and a quick reference table.
Temperature Converter
°F → °C| Fahrenheit (°F) | Celsius (°C) | Kelvin (K) | Description |
|---|---|---|---|
| −40 | −40 | 233.15 | F and C are equal |
| 0 | −17.78 | 255.37 | Very cold winter day |
| 32 | 0 | 273.15 | Freezing point of water |
| 50 | 10 | 283.15 | Cool day |
| 68 | 20 | 293.15 | Comfortable room temp |
| 72 | 22.22 | 295.37 | Room temperature |
| 98.6 | 37 | 310.15 | Body temperature |
| 100 | 37.78 | 310.93 | Just above body temp |
| 212 | 100 | 373.15 | Boiling point of water |
Free Online Fahrenheit to Celsius Converter
The SmarterSources Fahrenheit to Celsius Converter lets you instantly convert temperatures between the Fahrenheit and Celsius scales. Whether you are cooking, checking a weather forecast from another country, adjusting a thermostat, or completing a science assignment, this tool gives you accurate, real-time results with a clear step-by-step breakdown of the math.
Understanding the Fahrenheit Scale
The Fahrenheit scale was proposed by physicist Daniel Gabriel Fahrenheit in 1724. On this scale, water freezes at 32°F and boils at 212°F at standard atmospheric pressure, creating a 180-degree interval between the two reference points. Fahrenheit is the primary temperature scale used in the United States, the Bahamas, Belize, the Cayman Islands, and Palau for everyday applications including weather reports, cooking, and indoor climate control.
Understanding the Celsius Scale
The Celsius scale (also called centigrade) was developed by astronomer Anders Celsius in 1742. It sets the freezing point of water at 0°C and the boiling point at 100°C under standard conditions, making it a base-10 system that is easy to work with. Celsius is the standard temperature scale in most of the world and is used universally in science, medicine, and engineering.
The Fahrenheit to Celsius Formula
To convert Fahrenheit to Celsius, subtract 32 from the Fahrenheit value and multiply by 5/9. Mathematically: °C = (°F − 32) × 5/9. To reverse the conversion from Celsius to Fahrenheit, multiply the Celsius value by 9/5 and add 32: °F = °C × 9/5 + 32. These formulas account for both the offset (32 degrees) and the ratio (180 Fahrenheit degrees = 100 Celsius degrees) between the two scales.
What About Kelvin?
Kelvin is the SI base unit of temperature and is widely used in scientific contexts. It shares the same degree size as Celsius but starts at absolute zero (−273.15°C), the lowest temperature theoretically possible. To convert Celsius to Kelvin, simply add 273.15: K = °C + 273.15. This tool automatically displays the Kelvin equivalent alongside your Fahrenheit and Celsius results.
Key Temperature Reference Points
Some temperatures are worth memorizing for quick mental conversions. Water freezes at 32°F / 0°C, a comfortable room temperature is about 72°F / 22°C, normal human body temperature is 98.6°F / 37°C, and water boils at 212°F / 100°C. The only temperature where Fahrenheit and Celsius are the same is −40 degrees.
Frequently Asked Questions
What is the formula to convert Fahrenheit to Celsius?
Subtract 32 from the Fahrenheit value and multiply by 5/9. The formula is °C = (°F − 32) × 5/9. For example, 72°F equals (72 − 32) × 5/9 = 22.22°C.
What is the formula to convert Celsius to Fahrenheit?
Multiply the Celsius value by 9/5 and add 32. The formula is °F = °C × 9/5 + 32. For example, 100°C equals 100 × 9/5 + 32 = 212°F (the boiling point of water).
At what temperature are Fahrenheit and Celsius the same?
−40 degrees is the only temperature where Fahrenheit and Celsius are equal. Set the two conversion formulas equal to each other and solve, and you arrive at −40. This is a useful trivia fact but also a handy sanity check when verifying conversion formulas.
What is normal body temperature in Celsius?
Normal human body temperature is approximately 37°C, which equals 98.6°F. However, modern research suggests the average has dropped slightly to around 36.6°C (97.9°F). Body temperature can also vary throughout the day and between individuals.
Is my data safe with this converter?
Yes. All conversions happen entirely in your browser using JavaScript. No temperature data is sent to any server, and nothing is stored or logged. Your inputs remain completely private.