Fahrenheit to Kelvin – Formula, Examples | °F to K Conversion

The measurement of temperature became possible in the 17th century. Many researchers came forward to find the various units for temperature. Fahrenheit and Kelvin were two of those units which were widely used till the 19th century.  The conversion of Fahrenheit to Kelvin is simple in terms of mathematical equations. After Celsius, F to K is the unit commonly known worldwide. The Fahrenheit scale is commonly used in the United  Nations. The Kelvin scale is also known as the absolute scale.

In this write-up, get to know the Fahrenheit to Kelvin formula for the conversion of the units of temperature, their history, uses, and more.

Fahrenheit Definition

Fahrenheit is a unit of measurement for temperature. This unit is widely sued in the United States of America. The scale of Fahrenheit is based on the freezing point of water at 32 degrees and its boiling point at 212 degrees. The interval between both the points of the unit is divided into equal parts of 180. The Fahrenheit degree is abbreviated as °F. 

Origin of Fahrenheit

A German scientist named Daniel Gabriel Fahrenheit made the temperature scale in the year 1724. Subsequently, throughout the 18th century, the Fahrenheit scale was widely used.  Since the measurement of temperature was a big problem. Fahrenheit invented the thermometer at the age of twenty-eight. He stunned the world with his discovery with a pair of thermometers that gave the same reading. Since the thermometer was invented, he had to name them something to mark out the different temperatures. The scale used by him came to be known as Fahrenheit. 

Zero was set as the lowest temperature by Fahrenheit as he can get a salt and water mixture to reach the point. Also, he took the average temperature of the human body as 96 as the second point on his scale. Then, he set the boiling point at 212 and the freezing point at 32. 

In the 18th and 19th centuries, when Britain conquered most of the world, the Fahrenheit scale became a standard measurement of temperature around the world.

The 20th century was more in favour of celsius as the unit of temperature. However, the use of Fahrenheit was not totally abolished. Even today, in some countries like the United States of America and the United Kingdom, the °F is used for weather forecasts. It is because the older generation of the countries is more familiar with the °Fahrenheit scale. The majority of the world has declined the use of Fahrenheit as the unit of temperature. 

Uses of Fahrenheit

There are several reasons why the Fahrenheit scale is still used, especially in the United States of America. The scale is convenient to use as compared to other temperature measurement scales. Since it is a temperature measurement unit, it can be used in several places for measuring the temperature. Here are a few uses of the Fahrenheit scale:

• For weather forecasts.
• To know the boiling and freezing point of water.
• For knowing the temperature of the human body.

Kelvin Definition

Kelvin is the thermodynamic unit of temperature measurement. This unit of temperature is used in the International System of Unit (SI System). The unit was previously defined as 100/27,316 of the equilibrium among the solid, liquid, and gaseous states, known as the triple point. But ever since the conference of Weights and Measures in 2018, the unit started to be defined as equal to the Boltzman Constant (1.380649 × 10−23 Joule per kelvin) from 30th May 2019. Kelvin is abbreviated as K. 

Origin of Kelvin

The Kelvin scale dates back to the 19th century. Lord Kelvin defined an absolute temperature in 1848 as per the Carnot Cycle. This absolute temperature is known to be the Kelvin unit of temperature measurement. On the absolute Kelvin scale, the zero point is equal to the 273.15 mark, which is below the Celsius scale. The Kelvin scale is used for measuring extreme cold and hot situations.  

The Kelvin scale is the primary unit of temperature in physical sciences. However, for day-to-day purposes, the Celsius scale remains to be a dominant unit of temperature.

Current Use of Kelvin

Since Kelvin is a unit of temperature measurement, it is used to give out temperatures in different situations. The unit is used for measuring the temperature of the liquid. It is also used for measuring the weather conditions of an area. The Kelvin scale is also used for measuring body temperatures. 

How to Convert Fahrenheit to Kelvin?

Both Fahrenheit and Kelvin have a common use: measure temperature. You might have thought that there is not much to convert when it comes to Fahrenheit to Kelvin conversion, but apparently, there is. A lot of scientific pieces of equipment use both of these units. However, it is quite easy to convert F to Kelvin (K). There are two methods to convert Fahrenheit to Kelvin.

Method #1

The first Fahrenheit to Kelvin formula for calculation is to:

• Subtract 32 from the temperature in Fahrenheit.
• Multiply the new value by 5.
• Then, divide the number by 9.
• Lastly, add 273.15 to the new value

The answer received after the following steps will be from Fahrenheit to Kelvin. Always remember that Fahrenheit has degrees that are not in the case of Kelvin.

For example:

Example 1:  50 F to K –

Step 1: Subtract 32 from the temperature: 50 – 32 = 18

Step 2: Multiply by 5: 18x5 = 90

Step 3: Divide by 9: 90/9 = 10

Step 4: Add 273.15 = 10+273.15 = 283.15

Hence, 50 F to K is 283.15 Kelvin.

Example 2: 100 F to Kelvin

Step 1: Subtract 32 from the temperature: 100 – 32 = 68

Step 2: Multiply by 5: 68x5 = 340

Step 3: Divide by 9: 340/9 = 37.77

Step 4: Add 273.15 = 37.77 + 273.15 = 310.92

Hence, 100 F to Kelvin is 310.92 Kelvin.

Method #2

The other method to convert F to Kelvin is by using the calculation method. This method is easy to perform using a calculator. Also, you can solve it easily on your own. Fahrenheit to Kelvin Formula (F to K Formula)  is as follows:

Temperature in Kelvin (K) = (Temperature in Fahrenheit + 459.67) x 5/9

For example:

1. To convert 50 F to K:

Temperature in Kelvin (K) = (50 + 459.67) x 5/9

Temperature in Kelvin (K) =  283.15

1. To convert 100 F to Kelvin:

Temperature in Kelvin (K) = (100 + 459.67) x 5/9

Temperature in Kelvin (K) = 310.928

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Difference between Fahrenheit and Kelvin

The Fahrenheit to Kelvin differences are listed below:

Relationship between Fahrenheit and Kelvin

Both of the units are used for the purpose of temperature measurement. The relationship between Fahrenheit to Kelvin is that the degree Fahrenheit scale is made up of small temperature measuring units while the Kelvin scale has units of 1.8 °F. When defined mathematically, the relationship between F to Kelvin is

K = 273 + (5/9)*(F-32)

The above-mentioned relationship is used as the Fahrenheit to Kelvin formula for conversion. 

Fahrenheit to Kelvin Conversion Chart

FAQ’s about Fahrenheit to Kelvin