Absolute length in CSS3:

 Absolute lengths are specified when the Web page designer is aware of
the physical properties of the output device. These are specific and feed values

Absolute length	Description
in	Specifies the size and inches where one inch =2.54 centimeter.
cm	Specifies the in centimeters.
mm	Specifies the size in millimeters
pt	Specifies the size in points, where 1 point = 1/72th of an inch
pc	Specifies the size in picas, where 1 pica = 12 points

Example.

ol  {

  Font-family: Times New Roman;

Font-size: 0.5cm;

}

td {

       Font-size=0.2in;

}

caption {

           Font-size=3mm; }

  

   Ø Percentages: 

      

        Percentage allows specifying the length of the content, which is          relative to      another value.

    H1{

    Font-size=120%;

   Line-hight:200%;

}

The CSS code specifies the styles for the H1 element. The font-size property is set to a value of 120%. This means that the size of the header will appear 20% greater than Its current size. The line-height property is set to the value 200%. This means that the height of the line will be double the value of the font-size property.