How to convert fahrenheit to celsius

How to Convert Fahrenheit to Celsius

Toggle between the temperature scales with a formula

ThoughtCo. / Hugo Lin

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 know how to convert one to the other, especially when traveling or doing scientific research.

Key Takeaways: Fahrenheit to Celsius

How to Convert Temperatures

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

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:

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:

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

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:

(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:

Quick Conversion Table

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

-40 F-40 C-30 F-34 C-20 F-29 C-10 F-23 C0 F-18 C10 F-12 C20 F-7 C32 F0 C40 F4 C50 F10 C60 F16 C70 F21 C80 F27 C90 F32 C100 F38 C

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 in the Bahamas, Belize, and the Cayman Islands for most temperature measurements.

Fahrenheit To Celsius Calculator – °F to °C

This page features a Fahrenheit to Celsius:

Fahrenheit To Celsius Conversion Calculator

Enter A Temperature

Use this calculator to quickly convert a temperature from Fahrenheit (°F) to degrees Celsius (°C).

This calculator accepts values using both scales and so, if required, can be used to convert temperatures in Celsius back to Fahrenheit.

Fahrenheit To Celsius Formula

The worked example below shows how to convert to Celsius from Fahrenheit using this formula.

If are using this formula to manually convert a temperature, check your result with the calculator.

How To Convert Fahrenheit To Celsius (°F to °C)

Worked Example

Convert 70 Fahrenheit (°F) to Celsius (°C)

check this result with the conversion calculator

Albert Einstein is shown for illustrative purposes.
Anders Celsius (1701–1744), is the proponent of the Celsius temperature scale.

Fahrenheit To Celsius Conversion Table

Fahrenheit To Celsius Conversions

Fahrenheit (°F)	Celsius (°C)
-459.67 °F	-273.15 °C	absolute zero
32 °F	0 °C	freezing point of water
50 °F	10 °C
68 °F	20 °C
86 °F	30 °C
104 °F	40 °C
122 °F	50 °C
140 °F	60 °C
158 °F	70 °C
176 °F	80 °C
194 °F	90 °C
212 °F	100 °C	boiling point of water

Fahrenheit to Celsius

Note: Fractional results are rounded to the nearest 1/64. For a more accurate answer please select ‘decimal’ from the options above the result.

Note: You can increase or decrease the accuracy of this answer by selecting the number of significant figures required from the options above the result.

Note: For a pure decimal result please select ‘decimal’ from the options above the result.

Fahrenheit to Celsius formula

Quick and easy Fahrenheit to Celsius conversion

There’s a simple rule to convert Fahrenheit to Celsius that should be good enough for general use. Simply take 30 off the Fahrenheit value, and then half that number.

Note that this value isn’t perfect, but it might save you having to reach for a calculator (or our site!)

Absolute Zero	-459.67°F	-273.15°C
Parity	-40°F	-40°C
Zero	0°F	-17.78°C
Freezing point	32°F	0°C
Body Temperature	98.6°F	37°C
Boiling point	212°F	100°C

Definition of Fahrenheit and Celsius

The scientific definition of Celsius is now defined against degrees Kelvin. Zero degrees Celsius is 273.15K. One degree Celsius is equal to one Kelvin, so we can say that the boiling point of water is equal to 273.15 + 100 = 373.15 Kelvin.

Fahrenheit to Celsius formula

Why is converting Fahrenheit to Celsius so complicated?

Most things we measure – length, width, time etc. have one thing in common – their values all start from zero. We all know exactly how long zero centimeters or inches is, and can convert zero of any of those units into another type of unit very easily. Zero centimeters = zero meters = zero inches. Taking inches and centimeters as an example, to go from zero inches to 1 inch we need to add one inch. So far, so obvious.
Similarly, to go from zero centimeters to 1 centimeter, we need only add 1 centimeter. The only difference between adding one inch or one centimetre is the amount of distance we’re adding. The relationship between an inch and a centimetre is that 1 inch is 2.54 centimetres. So we can say that adding 1 inch is the same as adding 2.54 centimetres. Because they both start at zero, the formula to convert between the two very easy (in = cm * 0.39370)

Temperature units aren’t built in the same simple way, because they don’t all start in the same place at zero. If we pegged absolute zero to be 0°F, 0°C and 0K, converting between them would be much easier, but Fahrenheit and Celsius were defined before we could tell where absolute zero was, and as a result Fahrenheit, Celsius and Kelvin all start from different values.

Because these temperature units don’t share a common zero point, we need to add or subtract an offset before we do our division or multiplication. It’s not a difficult extra step, but it seems to be something that can cause confusion. As a rough rule of thumb:
To go from Fahrenheit to Celsius, take 30 off the Fahrenheit value, and then half that number.
For a 100% accurate answer, subtract 32 and divide by 1.8 (or use the calculator above!)

Fahrenheit to celsius conversion

Type in either field to convert from Fahrenheit to Celsius or from Celsius to Fahrenheit:

Fahrenheit is a temperature scale used for describing temperatures in Fahrenheit degrees (°F).

It is most commonly used in the United States in weather forecasts and to describe temperatures inside houses, offices, etc.

So the formula becomes: F = (C x 2) + 30

For example: (25C x 2) + 30 = 80F. The accurate answer is 77F but if you don’t have a calculator handy and can’t multiply and divide using fractions then this formula will give you a good idea that you can use in everyday situations.

Another simple conversion method from C to F is to double the celsius, subtract 10%, add 32. For example: 100C = 2×100=200,200-20=180,add 32=212F

Because of the complex convesion formula people often use fahrenheit to celsius calculators to convert temperatures. Remembering a few °C and °F pairs can be useful in everyday life.

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Celsius, or centigrade, is also a temperature scale that describes temperatures in Celsius degrees (°C) and it is used in (almost) everywhere else outside the US.

212 °F = 100 °C = boiling point of water
32 °F = 0 °C = freezing point of water

The conversion formulas between °F and °C are:

Conversion Chart

Quickly convert common temperatures using the fahrenheit to celsius conversion chart below:

Fahrenheit To Celsius Formula
– Convert °F to °C

Fahrenheit To Celsius Formula

Use this formula to convert a temperature in Fahrenheit (K) to Celsius (°F).

If required, there are worked examples below which use this formula to show how to convert a temperature in Fahrenheit to a temperature in Celsius.

As with any math calculation and conversion, it’s good practice to double check your results. If you are using this formula for your own conversions, you can check your result with the Fahrenheit to Celsius calculator.

Temperature scales are usually named after the person who created them. The temperature scales used in this formula were created by Daniel Gabriel Fahrenheit (1686 – 1736), and Anders Celsius (1701–1744).

I am unsure if it was Anders Celsius or Daniel Gabriel Fahrenheit who created this conversion formula. Literature indicates that the Fahrenheit scale was invented in 1724 and the Celsius (Centigrade) scale invented in 1742. From these dates, it’s probable that Anders Celsius invented this conversion formula.

How To Convert Fahrenheit To Celsius

Worked Example 1

How To Convert 0 Fahrenheit (°F) to Celsius (°C)

check this result with the conversion calculator

Worked Example 2

How To Convert 100 Fahrenheit (°F) to Celsius (°C)

check this result with the conversion calculator

Albert Einstein & his impostor are shown for illustrative purposes.
Anders Celsius (1701–1744), is the proponent of the Celsius temperature scale.

Formula Or Equation?

Is a formula, an equation, or both used to convert Fahrenheit to Celsius?

* ‘formulae’, (and formulas), are the plural of formula

Источники информации:

• http://www.srhartley.com/fahrenheit-to-celsius/conversion-calculator/
• http://www.metric-conversions.org/temperature/fahrenheit-to-celsius.htm
• http://www.fahrenheittocelsius.com/
• http://www.srhartley.com/fahrenheit-to-celsius/formula/