Temperature is a physical quantity which gives the measure of hotness and coldness on a numerical scale. The most commonly used scales for measuring temperature are the Fahrenheit, Celsius and Kelvin.
For example, a person from Europe might not know 129 degrees Fahrenheit would be a hot or cold day since they are not familiar with the unit. So in this case the temperature conversion come in handy!

Fahrenheit Celsius
-40 -40
-38 -36.4
-36 -32.8
-30 -22
-22 -7.6
24 75.2
28 82.4
32 89.6
34 93.2
40 104
43 109.4
85 185
90 194
95 203
97 206.6
99 210.2
103 217.4
142 287.6
146 294.8
151 303.8

Formulas: F = C$\times$ $\frac{9}{5}$ + 32

C = (F - 32)$\times$ $\frac{5}{9}$
Kelvin is the absolute zero temperature scale and on the scale coldest temperature possible is -$273^{0}$C having a value of 0 Kelvin (0K) and is called the absolute zero. Kelvin scale will not have negative numbers as Kelvin scale does not contain negative numbers.

Absolute Zero Temperature = 0K = - 273.15

Centigrade = -459.67 Fahrenheit degrees.

To convert a Celsius temperature into Kelvin temperature add 273 to the Celsius temperature.

K = C + 273.15
If the body temperature is determined by placing a thermometer under the armpit it is known as axillary temperature. There will be difference in reading the temperature as the axillary temperature is taken outside the body. The normal axillary temperature range is between 96.6° F and 98° F or 35.9° C to 36.7° C.
Rankine scale is absolute zero scale and the symbol used is $^{0}$R. Rankine degree is equal to one degree Fahrenheit.
A temperature of -459.67$^{0}$F is exactly equal to $0^{0}$R.
The degree Fahrenheit, $^{0}$F is a unit used to measure temperature named after Gabriel Fahrenheit. In the Fahrenheit scale of temperature the freezing point of water is 32 degrees and the boiling point is 212 degrees.
The formula for converting Celsius to Fahrenheit is:

C = $\frac{5}{9}$ (F - 32)

where C : Temperature in Celsius.
F : Temperature in Fahrenheit.
The degree Celsius, $^{0}$C is a unit used to measure temperature first proposed by Anders Celsius. In the Celsius scale temperature the freezing point of water is 0 degrees and the boiling point is 100 degrees at standard atmospheric pressure.
The formula for converting Fahrenheit to Celsius is:

F = C$\times$ $\frac{9}{5}$ + 32

where C : Temperature in Celsius
F : Temperature in Fahrenheit.

The formulas used to convert between temperatures are:

C = $\frac{5}{9}$ (F - 32)

F = C$\times$ $\frac{9}{5}$ + 32

K = C + 273.15

where C : Temperature in Celsius
F : Temperature in Fahrenheit and
K : Temperature in Kelvin.

Solved Examples

Question 1: How many degree Celsius are 80 degrees Fahrenheit?
Solution:
 
The formula for converting Celsius to Fahrenheit is:

C = (F - 32) $\times$ $\frac{5}{9}$ 

Plug in 80 instead of F in the above formula and simplify.

C = (80 - 32) $\times$ $\frac{5}{9}$ 

  = 48 $\times$ $\frac{5}{9}$

C =   26.67

Therefore, 26.67$^{0}$C  will give 80$^{0}$F.
 

Question 2: Convert 88$^{0}$C to kelvin.
Solution:
 
The formula used for converting Celsius to kelvin temperature is
K = C + 273
K = 88 + 273
K = 361
 

Question 3: Convert 70$^{0}$C to Fahrenheit.
Solution:
 
The formula for converting Fahrenheit to Celsius  is:      
               
F = C$\times$ $\frac{9}{5}$ + 32

Substitute 70 in place of C above, we get

F = 70 $\times$ $\frac{9}{5}$ + 32

= 158