Temperature Conversion Formula

Temperature is a measurement of how hot or cold something is. Temperature conversion formulas refer to the mathematical equations used to convert temperature from one unit to another. There are three temperature units including Kelvin, Celsius, and Fahrenheit. Hence, we need Temperature Conversion Formula to convert temperature given in one unit to other unit.

According to the Kelvin scale, the freezing point of water is 273.15K and the boiling point is 373.15K. According to the Fahrenheit scale, the freezing point of water is 32°F and the boiling point is 212°F. According to the Celsius scale, the freezing point of water is 0°C and the boiling point is 100°C. Now let’s learn about the various conversion formulas in detail in this article.

What is Temperature?

The degree or intensity of heat contained in a substance or system, represented on a comparative scale and displayed by a thermometer, is known as temperature.

Temperature, in other terms, is the measurement of a body’s hotness or coolness in degrees Celsius, Kelvin, and Fahrenheit. The amount of heat released or absorbed determines the temperature difference. The Kelvin temperature unit is used in the S.I. system of measurement.

What are Temperature Conversion Formulas?

Temperature Conversion Formulas are used to convert various units of temperature. There are three main conversions of temperature which include:

• Celsius and Kelvin Conversion
• Fahrenheit and Kelvin Conversion
• Celsius and Fahrenheit Conversion

Units of Temperature

The temperature of the substance is the measurement of the degree of hotness or coldness of any substance or object. There are various units which are used to measure the temperature. The three basic units which are used to measure the temperature of any object are

• Celsius (°C)
• Fahrenheit (°F)
• Kelvin (K)

Further in this article, we will learn more about these units in detail.

Celsius

Andres Celsius in 1742 was the first to use a scale to measure the temperature. Hence, the scale is called the Celsius scale, which is also called centigrade, in this scale, temperature is represented as °C. The freezing point of water in this scale is 0°C, the boiling point of water is 100°C and the normal human body temperature in this scale is 37°C.

Fahrenheit

Daniel Gabriel Fahrenheit also proposed a scale to measure temperature which is named after him as Fahrenheit scale. In this scale, the temperature is represented as °F. The freezing point of water in this scale is 32°F, the boiling point of water is 212°F and the normal human body temperature in this scale is 98.6°C.

Kelvin

The SI unit for temperature is Kelvin. It is named after the famous physicist William Thomson Baron Kelvin. It is represented using the symbol K. Here in representing the temperature in kelvin we do not use the degree symbol (°). The freezing point of water in this scale is 273 K, the boiling point of water is 373 K and the normal human body temperature in this scale is 310 K.

Measurement of Temperature

Temperatures are often expressed as numerical values in a set of units. On different temperature scales, the same temperature has different readings. 

Fahrenheit, Celsius, and Kelvin units for measuring temperature. In thermometers, any of the three units are used to measure the temperature. Changing the value of temperature from one scale unit to another is referred to as temperature conversion. 

The image of the thermometer given below shows the temperature in °C and °F.

There are several methods for converting temperatures. Water has a freezing point of 273.15K and a boiling point of 373.15K on the Kelvin scale. Water has a freezing point of 32°F and a boiling point of 212°F on the Fahrenheit scale. Water has a freezing point of °C and a boiling point of 100°C on the Celsius scale.

(C / 5) = {(F-32) / 9} = {(K-273.15) / 5}

where, 

• C is Celsius scale
• F is Fahrenheit scale
• K is Kelvin scale

Temperature Conversion Celsius and Kelvin 

The temperature in the Celsius scale and Kelvin scale can be interchanged with each other using the following expression given below,

C = K – 273.15

K = C + 273.15

where, 

• C is Celsius scale
• K is Kelvin scale

Example: Convert 100 degrees Celsius to Kelvin.

Solution:

K = C+273.15

K = 100+273.15

K = 373.15

K = 373.15 Kelvin

Temperature Conversion Celsius and Fahrenheit

The temperature in the Celsius scale and Fahrenheit scale can be interchanged with each other using the following expression given below,

C / 5 = (F – 32) / 9

where,

• C is Celsius scale
• F is Fahrenheit scale

Example: Convert 100° Celsius to Fahrenheit.

Solution:

C / 5 = (F-32) / 9

C × 9 / 5 = F – 32

C = 100° C (given)

F – 32 = 100 × 9 / 5
          = 180

F = 180+32
   = 212

F = 212 Fahrenheit

Temperature Conversion Fahrenheit and Kelvin

The temperature in the Fahrenheit scale and Kelvin scale can be interchanged with each other using the following expression given below,

K = (F − 32) × 5⁄9 + 273.15

F = (K – 273.15) × 9⁄5 + 32

where,

• C is Celsius scale
• F is Fahrenheit scale
• K is Kelvin scale

Example: Convert 100 F to Kelvin.

Solution:

F = 100 (given)

K = (F − 32) × 5⁄9 + 273.15

K = (100 − 32) × 5⁄9 + 273.15

K = 68 × 5⁄9 + 273.15

K = 37.78 + 273.15

K = 310 .92 Kelvin

Temperature Conversion Formula Table

Temperature Conversion is required in various activities in our daily life, hence to learn temperature conversion is very important. Conversion between various tables can be achieved using the following table.

Unit	Celsius	Fahrenheit	Kelvin
Celsius (C)	°C	(9⁄5)×C + 32	C + 273.15
Fahrenheit	(5⁄9)×(F − 32)	°F	(5⁄9)×(F − 32)+ 273.15
Kelvin	K – 273.15	(9⁄5)×(K – 273.15) + 32	K

Temperature Conversion Table

The temperature conversion table converts various temperatures that are generally used by us, i.e. it includes the freezing point of water, the boiling point of water, and the normal body temperature of humans, in all units of temperature.

Kelvin	Celsius	Fahrenheit
273.15 K (freezing point of water)	0° C	32 °F
293.15 K (the temperature at STP)	20° C	68 °F
310.15 K (Normal body temperature)	37°C	98.6 °F
373.15 K (boiling point of water)	100°C	212.0 °F

Device to Measure Temperature

There are several materials whose properties change with the temperature in a repeatable and predictable manner and this forms a way for accurate temperature measurement. The glass thermometer is one of the most common devices for measuring temperature. The glass thermometer is a glass tube filled with mercury or some other liquid, in which mercury acts as the working fluid. 

Temperature increase causes the fluid to expand and mercury changes its properties with respect to the temperature. As the temperature increases the volume of mercury also increases. So, the temperature can be determined by measuring the volume of the fluid and temperature can be read simply by observing the level of the fluid in the thermometer. Generally, we use a mercury-in-glass thermometer.

Tips and Tricks

To remember the temperature conversion formula without fractions follow these,

•  5(°F)= 9(°C) + 160
• To directly convert Celsius to Fahrenheit multiply it by 1.8 and add 32.
• To find the approximate temperature in degrees Fahrenheit, subtract 30 from the Celsius value and then divide by 2.

Examples on Temperature Conversion

Example 1: Calculate the temperature 75° C on the Kelvin scale.

Solution:

(C / 5) = ((K-273.15) / 5)

C = K – 273.15

K = C + 273.15

K = 75 + 273.15

K= 348.15

K = 348.15 Kelvin

Example 2: Convert the temperature to Fahrenheit, which is equivalent to 326 K on the Kelvin scale.

Solution:

((F-32) / 9) = ((K-273.15) / 5)

F – 32 = 9(K-273.15) / 5)

F – 32 = 9(326-273.15) / 5)

F – 32 = 475.65/5

F – 32 = 95.13

F = 95.13 + 32 = 127.13

F = 127.13° F

Example 3: Convert the temperature 296 K into Celsius.

Solution: 

K = 286 K (given)

Now, we know,

C = K – 273.15

C = 296 – 273.15

C = 22.85

Thus, the temperature in the Celsius scale is 22.85°C.

Example 4: Convert 30°C into Kelvin.

Solution:

We know that, K = C + 273.15

C = 30°C (given)

K = 30 + 273.15 K 

K = 303.15

Example 5: Convert 223°F to Kelvin.

Solution:

We know that, K = (F − 32) × 5⁄9 + 273.15

F = 223°F

K = (223 – 32) × (5/9) + 273.15

K = 191 × (5/9) + 273.15

K = 106.11 + 273.15

K = 379.26  K

223°F = 379.26  K

Practice Questions on Temperature Formula

Q1: The boiling point of a Liquid is 393K. What is its boiling point in ℃ and ℉?

Q2: The body temperature of a person suffering from fever is 102℉. What is his temperature in ℃?

Q3: Convert 95℃ into Kelvin and Fahrenheit.

Q4: Find out the temperature at which ℃ and ℉ are equal.

FAQs on Temperature Conversion Formula

1. What is Temperature Conversion Formula?

Temperature conversion formulas help us to convert temperature from one unit to another. The most commonly used scales for temperature measurement include Kelvin, Celsius, and Fahrenheit.

2. What are the Units of Temperature?

There are three unit of temperatures,

• Kelvin (K)
• Celsius (C)
• Fahrenheit (F)

Kelvin is the S.I. unit of temperature measurement.

3. How to Convert Temperature from Celsius to Fahrenheit?

Celsius to Fahrenheit conversion can quickly be achieved by multiplying 1.8 by the Celsius value and adding 32 to get the Fahrenheit equivalent.

4. Which Scale is better Celsius or Fahrenheit?

The Celsius scale and Fahrenheit scale both are useful in their own ways. The celsius scale is good for measuring the temperature of the water, whereas the Fahrenheit scale is used for more general purposes.

5. How to Convert Temperature into Celsius?

We can convert temperature into Celsius using the formulas,

• C = K – 273.15
• C / 5 = (F-32) / 9

6. How to Convert Temperature from Celsius to Fahrenheit?

We use the following formula in converting temperature from Celsius to Fahrenheit,

F = 9/5×C + 32

7. At what Temeprature ℃ and ℉ are Equal?

Celsius and Fahrenheit are equal at -40° temperature.