How to Convert Fahrenheit to Celsius (2024)

Fahrenheit and Celsius are the scales most often used for reporting room, weather, and water temperatures. The Fahrenheit scale is used in the United States, while the Celsius scale is used worldwide.

Indeed, most countries around the world measure their weather and temperatures using the relatively simple Celsius scale. But the United States is one of just a few remaining countries that use Fahrenheit, so it's important for Americans to knowhow to convert one to the other, especially when traveling or doing scientific research.

Key Takeaways: Fahrenheit to Celsius

  • Fahrenheit is the common temperature scale in the United States, while Celsius is in use worldwide.
  • The formula for converting Fahrenheit to Celsius is C = 5/9(F-32).
  • Fahrenheit and Celsius are the same at -40°. At ordinary temperatures, Fahrenheit is a larger number than Celsius. For example, body temperature is 98.6 °F or 37 °C.

How to Convert Temperatures

First, you need the formula for converting Fahrenheit (F) to Celsius (C):

  • C = 5/9 x (F-32)

The notation C represents the temperature in Celsius, and F is the temperature in Fahrenheit. After you know the formula, it is easy to convertFahrenheit to Celsius with these three steps.

  1. Subtract 32 from the Fahrenheit temperature.
  2. Multiply this number by five.
  3. Divide the result by nine.

For example, suppose the temperature is 80 degrees Fahrenheit and you want to know what the figure would be in Celsius. Use the above three steps:

  1. 80 F – 32 = 48
  2. 5 x 48 = 240
  3. 240 / 9 = 26.7
Read MoreSimplify Temp Conversion: Fahrenheit to CelsiusBy Anne Marie Helmenstine, Ph.D.

So the temperature in Celsius is 26.7 °C.

Fahrenheit to Celsius Example

If you want to convert a normal human body temperature (98.6 °F) to Celsius, plug the Fahrenheit temperature into the formula:

  • C = 5/9 x (F - 32)

As noted, your starting temperature is 98.6 F. So you would have:

  • C = 5/9 x (F - 32)
  • C = 5/9 x (98.6 - 32)
  • C = 5/9 x (66.6)
  • C = 37 C

Check your answer to ensure it makes sense. At ordinary temperatures, a Celsius value is always lower than the corresponding Fahrenheit value. Also, it's helpful to keep in mind that the Celsius scale is based on the freezing and boiling points of water, where 0 °C is the freezing point and 100 °C is the boiling point. On the Fahrenheit scale, water freezes at 32 °F and boils at 212 °F.

Conversion Shortcut

You often don't need an exact conversion. If you're traveling to Europe, for example, and you know the temperature is 74 °F, you might want to know the approximate temperature in Celsius. Here is a quick tip for making an approximate conversion:

Fahrenheit to Celsius:Subtract 30 from the Fahrenheit temperature and then divide by two. So, using the approximation formula:

  • 74 F – 30 = 44
  • 44 / 2 = 22 °C

(If you go through the previous formula's calculations for the exact temperature, you arrive at 23.3.)

Celsius to Fahrenheit:To reverse the approximation and convert from 22 °C to Fahrenheit, multiply by two and add 30. So:

  • 22 C x 2 = 44
  • 44 + 30 = 74 °C

Quick Conversion Table

You can save even more time by using predetermined conversions.The Old Farmer's Almanacoffers this table for making quick conversions from Fahrenheit to Celsius.

Fahrenheit

Celsius

-40 F-40 C
-30 F-34 C
-20 F-29 C
-10 F-23 C
0 F-18 C
10 F-12 C
20 F-7 C
32 F0 C
40 F4 C
50 F10 C
60 F16 C
70 F21 C
80 F27 C
90 F32 C
100 F38 C

Note how the Fahrenheit and Celsius scales read the same temperature at -40°.

Invention of Fahrenheit

While you're mastering these conversions, it might be interesting to learn how the Fahrenheit temperature scale came into existence. The first mercury thermometer was invented by German scientist Daniel Fahrenheit in 1714. His scale divides the freezing and boiling points of water into 180 degrees, with 32 degrees as water's freezing point, and 212 as its boiling point.

On Fahrenheit's scale, zero degrees was determined as the temperature of a temperature-stable brine solution of ice, water, and ammonium chloride. He based the scale on the average temperature of the human body, which he originally calculated at 100 degrees. (As noted, it's since been adjusted to 98.6 degrees Fahrenheit.)

Fahrenheit was the standard unit of measure in most countries until the 1960s and 1970s when it was replaced with the Celsius scale in a widespread conversion to the more useful metric system. In addition to the United States and its territories,Fahrenheit is still used inthe Bahamas, Belize, and the Cayman Islands for most temperature measurements.

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Your Citation

Helmenstine, Anne Marie, Ph.D. "How to Convert Fahrenheit to Celsius." ThoughtCo, Apr. 5, 2023, thoughtco.com/fahrenheit-to-celsius-formula-609230.Helmenstine, Anne Marie, Ph.D. (2023, April 5). How to Convert Fahrenheit to Celsius. Retrieved from https://www.thoughtco.com/fahrenheit-to-celsius-formula-609230Helmenstine, Anne Marie, Ph.D. "How to Convert Fahrenheit to Celsius." ThoughtCo. https://www.thoughtco.com/fahrenheit-to-celsius-formula-609230 (accessed July 5, 2024).

How to Convert Fahrenheit to Celsius (2024)

FAQs

How to Convert Fahrenheit to Celsius? ›

Fahrenheit to Celsius, subtract 30 then divide by 2. Celsius to Fahrenheit, multiply by 2 then add 30.

How to convert Fahrenheit to Celsius easily? ›

Fahrenheit to Celsius, subtract 30 then divide by 2. Celsius to Fahrenheit, multiply by 2 then add 30.

How do you convert Celsius to Fahrenheit answer? ›

The formula to convert Celsius to Fahrenheit is given by: °F = °C × (9/5) + 32. By using this formula, we can convert any given temperature from Celsius to Fahrenheit (C to F).

What is the easiest trick to convert Celsius to Fahrenheit? ›

So if you are like me, and are familiar with temperature in Fahrenheit, just remember how to get C to F: Double it and add 30. If you are more familiar with Celsius, you more often only need to convert F to C. So just remember: Take away 30 and halve it.

How do you convert exact Fahrenheit to Celsius? ›

Fahrenheit °F to Celsius °C Formula

°C equals °F minus 32, divided by 9/5. Alternatively, since 9/5 = 1.8 we can say °C equals °F minus 32, divided by 1.8.

What is the cheat to convert Celsius to Fahrenheit? ›

When converting Celsius to Fahrenheit, the formula is: (°C * 1.8) + 32 = °F. You multiply 1.8 to the number of degrees Celsius, then add that number to 32. There are tricks that will help you convert. One approximation is to double the Celsius temperature and subtract 10%, then add 32 for a ballpark figure.

What is the formula for temperature conversion? ›

To convert Fahrenheit to Celsius, we use the formula F = 1.8C + 32. To convert Celsius to Fahrenheit, we use the formula C = (F - 32) / 1.8. To convert Kelvin to Celsius, we use the formula C = K - 273.15. To covert Celsius to Kelvin, we use the formula K = C + 273.15.

How do you convert F to C without a calculator? ›

For a quick and dirty approximation, subtract 30 from the Fahrenheit and divide by two to get the Celsius; or to go the other way, double it and add 30. Otherwise, remember some exact Celsius to Fahrenheit conversions: 10 to 50, 15 to 59, 20 to 68, 25 to 77.

What is the algorithm for converting Celsius to Fahrenheit? ›

The algorithm to convert from Celsius to Fahrenheit is the temperature in Celsius times 9/5, plus 32.

What is the formula for changing Fahrenheit to Celsius? ›

What is the Formula to Convert Fahrenheit to Celsius? The Fahrenheit to Celsius formula is expressed as °C = (°F - 32) × 5/9; in which the value of F (Fahrenheit) is substituted and we get the value in Celsius. This formula converts the given temperature value from Fahrenheit to Celsius.

What is the formula for the Fahrenheit scale? ›

The Fahrenheit temperature scale is used in the United States; the Celsius, or centigrade, scale is employed in most other countries and for scientific purposes worldwide. The conversion formula for a temperature that is expressed on the Celsius (°C) scale to its Fahrenheit (°F) representation is: °F = (9/5 × °C) + 32.

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