Fahrenheit to Celsius Converter

This calculator converts any temperature from Fahrenheit to Celsius using the exact formula C = (F − 32) × 5/9, so you get a precise result rather than a rough guess. Enter a temperature in Fahrenheit, or click a quick preset such as 32°F (freezing), 72°F (room temperature), 98.6°F (body temperature), 212°F (boiling) or 350°F (oven), and the result updates instantly as you type. The main result shows your Celsius equivalent to two decimal places, along with the same temperature converted to Kelvin and Rankine, plus your original Fahrenheit figure echoed back for reference. Below the result, a working box breaks the calculation down step by step, subtracting 32 from your Fahrenheit value and multiplying by 5/9, so you can see exactly how the answer was reached. A reference table further down lists common conversions, from the -40 degree crossing point where both scales read the same, through water's freezing and boiling points, to typical oven and body temperatures, useful for cooking, weather, health or travel. Because the conversion formula is fixed by international standard and never changes, the figures here are exact rather than approximate, and you can rely on them for recipes, overseas weather forecasts, thermometer readings, or converting technical data between the two scales.

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Exact formula  The Fahrenheit-to-Celsius conversion is defined by international standards and does not change.
°F
Quick presets:

Result

22.22
degrees Celsius (°C)
Kelvin
295.37 K
Rankine
531.67 °R
Input (°F)
72 °F
C = (72 − 32) × 5/9 = 40 × 0.5556 = 22.22°C

Common Fahrenheit to Celsius Reference

Fahrenheit (°F)Celsius (°C)Reference point
-40°F-40.00°CScales are equal here
0°F-17.78°CBrine freezing point (Fahrenheit's original zero)
32°F0.00°CWater freezes (ice point)
37°F2.78°CTypical refrigerator
68°F20.00°CCool room temperature
72°F22.22°CComfortable room temperature
77°F25.00°CWarm room / NZ summer day
98.6°F37.00°CNormal human body temperature
104°F40.00°CHigh fever threshold
176°F80.00°CHot water (typical shower maximum)
212°F100.00°CWater boils (at sea level)
350°F176.67°CTypical baking temperature
425°F218.33°CHigh-heat roasting

The Fahrenheit to Celsius Formula

The conversion from Fahrenheit to Celsius uses the formula:

C = (F − 32) × 5/9

You subtract 32 because the two scales have different zero points: Celsius sets 0 at the freezing point of water, while Fahrenheit sets 32 at the same point. You then multiply by 5/9 (approximately 0.5556) to account for the different size of each degree. A Fahrenheit degree is smaller than a Celsius degree: there are 180 Fahrenheit degrees between freezing and boiling, but only 100 Celsius degrees.

Why Two Temperature Scales?

The Fahrenheit scale was developed by Daniel Gabriel Fahrenheit in 1724. He calibrated his scale using three fixed points: a brine freezing mixture (0°F), the freezing point of water (32°F), and human body temperature (originally 96°F, later refined to 98.6°F). The Celsius scale (originally called Centigrade) was proposed by Anders Celsius in 1742, using the more intuitive reference points of 0°C for water freezing and 100°C for water boiling at sea level.

Most of the world, including New Zealand, uses Celsius as the everyday temperature scale. The United States, a handful of Caribbean territories, and the Cayman Islands continue to use Fahrenheit for everyday purposes. Both scales are used in science; Kelvin (which shares the degree size of Celsius but starts at absolute zero) is the SI unit for thermodynamic temperature.

Worked Example (matches the default)

Converting 72°F (a comfortable room temperature) to Celsius:

  1. Subtract 32: 72 − 32 = 40
  2. Multiply by 5/9: 40 × 5 = 200, then 200 ÷ 9 = 22.22...
  3. Result: 22.22°C (rounded to two decimal places)

To also get Kelvin, add 273.15 to the Celsius value: 22.22 + 273.15 = 295.37 K.

Quick Mental Approximation

For a rough conversion in your head, use this shortcut: subtract 30, then halve the result. For example, 70°F becomes (70 − 30) / 2 = 20°C. This is slightly off (actual answer is 21.1°C) but useful for quick estimates when you do not have a calculator handy.

Related Calculators

Method: Standard international conversion formula C = (F − 32) × 5/9, as defined by the International Temperature Scale. The relationship between Fahrenheit and Celsius is exact and does not require periodic updates. Kelvin conversion uses K = C + 273.15 (BIPM, SI Brochure 9th edition). Rankine: R = F + 459.67.

This converter applies the exact mathematical formula and does not round inputs before calculation. Results are displayed to two decimal places. For scientific applications requiring more decimal places, use the formula directly.

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 temperature, then multiply the result by 5 and divide by 9. For example, 72°F gives (72 − 32) × 5/9 = 40 × 0.5556 = 22.22°C. The reverse formula (Celsius to Fahrenheit) is F = (C × 9/5) + 32.

What is 98.6°F in Celsius?

98.6°F equals exactly 37°C. This is normal human body temperature. The value 98.6°F was historically defined as the Fahrenheit equivalent of 37°C, so the conversion is exact: (98.6 − 32) × 5/9 = 66.6 × 5/9 = 37.0°C.

What temperature is the same in both Fahrenheit and Celsius?

The two scales are equal at −40 degrees. Both −40°F and −40°C are the same temperature. You can verify this with the formula: (−40 − 32) × 5/9 = −72 × 5/9 = −40°C. This is sometimes called the 'crossing point' of the two scales.

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