Fahrenheit to Celsius Converter

The Fahrenheit to Celsius Converter turns any temperature in degrees Fahrenheit (°F) into degrees Celsius (°C) using the exact formula °C = (°F − 32) × 5/9. Beyond the raw number, it places your temperature on a dual-scale thermometer, tells you what that reading feels like in the real world — from freezing to boiling — and shows the Kelvin and Rankine equivalents plus a full reference chart of common conversions.

Fahrenheit to Celsius Formula

The conversion has just two operations: shift the zero point, then rescale the degrees.

The − 32 first removes the Fahrenheit offset, so that water's freezing point (32 °F) becomes 0 — the same zero Celsius uses. The factor 5/9 (≈ 0.5556) then shrinks each Fahrenheit degree into a smaller Celsius step, because Fahrenheit splits the gap between water's freezing and boiling points into 180 degrees while Celsius uses only 100.

How to Convert Fahrenheit to Celsius (Worked Example)

To convert 77 °F to Celsius:

1. Subtract 32: 77 − 32 = 45
2. Multiply by 5/9: 45 × 5/9 = 25 °C

So 77 °F = 25 °C, a warm, pleasant day.

Quick Mental Shortcut

For a fast estimate without a calculator, subtract 30 and then halve the result. For 70 °F that gives about 20 °C (the exact answer is 21.1 °C). This trick is accurate enough for everyday weather but drifts at temperature extremes, so use the full formula when precision matters.

Fahrenheit to Celsius Chart (Common Values)

Fahrenheit vs Celsius: What is the Difference?

Fahrenheit (used mainly in the United States and a few other territories) sets water's freezing point at 32° and its boiling point at 212° at sea level. Celsius (used across most of the world and in science) sets those same two points at 0° and 100°. Because Fahrenheit packs 180 degrees into the same span that Celsius covers in 100, each Fahrenheit degree is smaller — exactly 5/9 of a Celsius degree. The two scales cross at a single temperature, -40°, where °F and °C read the same number.

Why Subtract 32 and Multiply by 5/9?

Daniel Gabriel Fahrenheit designed his scale in 1724 around three reference points, which happened to put water's freezing point at 32° and body temperature near 96°. Anders Celsius introduced his 0–100 water-based scale in 1742. When you convert from Fahrenheit to Celsius, the − 32 accounts for the different starting zero, and the 5/9 factor accounts for the different number of degrees per unit range — together they map one scale exactly onto the other.

How to Use This Converter

1. Enter the Fahrenheit temperature: Type any value into the input box, such as 98.6 or -12.5. Decimals and negative numbers are supported.
2. Click Convert to Celsius: The tool applies the formula °C = (°F − 32) × 5/9 instantly.
3. Read your results: See the Celsius value on the dual-scale thermometer, its real-world context, the step-by-step math, and the Kelvin and Rankine equivalents.

Frequently Asked Questions

What is the formula to convert Fahrenheit to Celsius?

The formula is °C = (°F − 32) × 5/9. Subtract 32 from the Fahrenheit value, then multiply by 5/9 (about 0.5556). For example, (68 − 32) = 36, and 36 × 5/9 = 20, so 68 °F equals 20 °C.

What is 32 degrees Fahrenheit in Celsius?

32 °F equals 0 °C. This is the freezing point of water at sea level.

What is 98.6 degrees Fahrenheit in Celsius?

98.6 °F equals 37 °C, which is the commonly cited normal human body temperature.

What is 212 degrees Fahrenheit in Celsius?

212 °F equals 100 °C, the boiling point of water at sea level.

At what temperature are Fahrenheit and Celsius equal?

Fahrenheit and Celsius read the same value at -40°. That is, -40 °F equals -40 °C — the only point where the two scales meet.

How do I quickly estimate Fahrenheit to Celsius in my head?

A quick mental shortcut is to subtract 30 from the Fahrenheit value and then halve it. For 70 °F that gives about 20 °C, close to the exact 21.1 °C. It is handy for everyday weather but not precise, so use the full formula when accuracy matters.

Additional Resources

• Celsius - Wikipedia
• Fahrenheit - Wikipedia