CSS | Units

Last Updated : 03 Dec, 2018

CSS has several different units for expressing the length and measurement. CSS units are needed to specify the measurement in stylesheet like padding:”5px”. Mainly there are two types of units in CSS.

Absolute Length
Relative Length

Absolute Length: It is not good for use on screen, cause screen size vary so much depending on the device used for that page it is recommended to use for print layout and where the output medium is known.
Absolute Length Units:

cm: centimeter
Syntax:

   font-size: 0.5cm;
   line-height: 0.1cm;

Example:

<html> 
    <head> 
        <title>CSS units</title> 
        <style> 
            .gfg { 
                font-size: 1.2cm; 
                font-weight:bold; 
            } 
            .geeks { 
                font-size: 0.5cm; 
                line-height: 0.1cm; 
            } 
        </style> 
    </head> 
    <body> 
        <div class = "gfg">GeeksforGeeks</gfg> 
        <div class = "geeks">A computer science portal for geeks</div> 
    </body> 
</html>                     

Output:
css units

mm: milimeter
Syntax:

   font-size: 5mm;
   line-height: 1mm;

Example:

<html> 
    <head> 
        <title>CSS units</title> 
        <style> 
            .gfg { 
                font-size: 12mm; 
                font-weight:bold; 
            } 
            .geeks { 
                font-size: 5mm; 
                line-height: 1mm; 
            } 
        </style> 
    </head> 
    <body> 
        <div class = "gfg">GeeksforGeeks</gfg> 
        <div class = "geeks">A computer science portal for geeks</div> 
    </body> 
</html>                     

Output:
css units

in: inches
Note: inches (1in = 96px = 2.54cm)
Syntax:

    font-size: 0.2in;
    line-height: 0.1in;

Example:

<html> 
    <head> 
        <title>CSS units</title> 
        <style> 
            .gfg { 
                font-size: .5in; 
                font-weight:bold; 
            } 
            .geeks { 
                font-size: .2in; 
                line-height: .1in; 
            } 
        </style> 
    </head> 
    <body> 
        <div class = "gfg">GeeksforGeeks</gfg> 
        <div class = "geeks">A computer science portal for geeks</div> 
    </body> 
</html>                     

Output:
css units

px: pixels
Note: pixels (1px = 1/96th of 1in)
Syntax:

   font-size: 20px;
   line-height: 10px;

Example:

<html> 
    <head> 
        <title>CSS units</title> 
        <style> 
            .gfg { 
                font-size: 40px; 
                font-weight:bold; 
            } 
            .geeks { 
                font-size: 17px; 
                line-height: 5px; 
            } 
        </style> 
    </head> 
    <body> 
        <div class = "gfg">GeeksforGeeks</gfg> 
        <div class = "geeks">A computer science portal for geeks</div> 
    </body> 
</html>                     

Output:
css units

pt:points
Note: points (1pt = 1/72 of 1in)
Syntax:

    font-size: 16pt;
    line-height: 8pt;

Example:

<html> 
    <head> 
        <title>CSS units</title> 
        <style> 
            .gfg { 
                font-size: 35pt; 
                font-weight:bold; 
            } 
            .geeks { 
                font-size: 15pt; 
                line-height: 5pt; 
            } 
        </style> 
    </head> 
    <body> 
        <div class = "gfg">GeeksforGeeks</gfg> 
        <div class = "geeks">A computer science portal for geeks</div> 
    </body> 
</html>                     

Output:
css units

pc: picas
Note: picas (1pc = 12 pt)
Syntax:

      font-size: 1pc;
      line-height: 0.5pc;

Example:

<html> 
    <head> 
        <title>CSS units</title> 
        <style> 
            .gfg { 
                font-size: 3pc; 
                font-weight:bold; 
            } 
            .geeks { 
                font-size: 1.3pc; 
                line-height: .2pc; 
            } 
        </style> 
    </head> 
    <body> 
        <div class = "gfg">GeeksforGeeks</gfg> 
        <div class = "geeks">A computer science portal for geeks</div> 
    </body> 
</html>                     

Output:
css units

Relative Length: It is good for use on screen, if screen size varies so much depending on the device then these relative length units are perfect because it changes with the different rendering mediums.

Relative Length Units:

em: Relative to the font size of that element.
Note: Here 2em meaning 2times the size of current font.
Syntax:

    font-size: 10px;
    line-height: 2em;

Example:

<html> 
    <head> 
        <title>relative unit</title> 
        <style> 
            p { 
                font-size: 15px; 
                line-height: 2em; 
            } 
    </style> 
    </head> 
    <body> 
        <p>GeeksforGeeks Line height: 2x10px = 20px</p> 
        <p>GeeksforGeeks Line height: 2x10px = 20px</p> 
        <p>GeeksforGeeks Line height: 2x10px = 20px</p> 
    </body> 
</html>                     

Output:
em unit

ex: Relative to the X(axis)-height of the current font.
Syntax:

font-size: 1ex;

Example:

<html> 
    <head> 
        <title>relative unit</title> 
        <style> 
            p { 
                font-size: 40px; 
            } 
            span { 
                font-size: 1ex; 
            } 
        </style> 
    </head> 
    <body> 
        <p>GeeksforGeeks:<span>A computer science 
        portal for geeks</span></p> 
    </body> 
</html>                     

Output:
ex unit image

ch: Relative to width of the 0.
Syntax:

font-size: 2ch;

Example:

<html> 
    <head> 
        <title>ch unit in CSS</title> 
        <style> 
            body { 
                font-size:50px; 
            } 
            div { 
                font-size: 1ch; 
            } 
        </style> 
    </head> 
    <body> 
        <p>GeeksforGeeks</p> 
        <div>A computer science portal for geeks</div> 
    </body> 
</html>                     

Output:
ch unit

rem: Relative to the browser base font-size.
Syntax:

font-size: 3rem;

Example:

<html> 
    <head> 
        <title>ch unit in CSS</title> 
        <style> 
            body { 
                font-size:4rem; 
            } 
            div { 
                font-size: 1.6rem; 
            } 
        </style> 
    </head> 
    <body> 
        <p>GeeksforGeeks</p> 
        <div>A computer science portal for geeks</div> 
    </body> 
</html>                     

Output:
ch unit

vw: Relative to 1% of the width of the viewport.
Syntax:

font-size: 10vw;

Example:

<html> 
    <head> 
        <title>vw unit</title> 
        <style> 
            h1 { 
                font-size: 4vw; 
            } 
        </style> 
    </head> 
    <body> 
        <h1>GeeksforGeeks</h1> 
        <p>A computer science portal for geeks</p> 
    </body> 
</html>                     

Output:
unit image

vh: Relative to 1% of the height of the viewport.
Syntax:

font-size: 10vh;

Example:

<html> 
    <head> 
        <style> 
            h1 { 
                font-size: 6vh; 
            } 
        </style> 
    </head> 
    <body> 
        <h1>GeeksforGeeks</h1> 
        <p>A computer science portal for geeks</p> 
    </body> 
</html>                     

Output:
unit image

vmin: Relative to 1% of the viewport’s smaller dimension.
Syntax:

font-size: 10vmin;

Example:

<html> 
    <head> 
        <title>vmin unit</title> 
        <style> 
            h1 { 
                font-size: 8vmin; 
            } 
        </style> 
    </head> 
    <body> 
        <h1>GeeksforGeeks</h1> 
        <p>A computer science portal for geeks</p> 
        <p>1vmin = 1vw or 1vh whichever is smaller.</p> 
    </body> 
</html>                     

Output:
vmin unit

vmax: Relative to 1% of the viewport’s larger dimension.
Syntax:

font-size: 20vmax;

Example:

<html> 
    <head> 
        <title>vmax unit</title> 
        <style> 
            h1 { 
                font-size: 5vmax; 
            } 
        </style> 
    </head> 
    <body> 
        <h1>GeeksforGeeks</h1> 
        <p>A computer science portal for geeks</p> 
        <p>1vmax = 1vw or 1vh whichever larger.</p> 
    </body> 
</html>                     

Output:
vmax

%: % unit sets the font-size relative to the current font-size.
Syntax:

font-size: 250%;

Example:

<html> 
    <head> 
        <title>CSS unit</title> 
        <style> 
            body { 
                font-size:250%; 
            } 
            div { 
                font-size: 17px; 
            } 
        </style> 
    </head> 
    <body> 
        <p>GeeksforGeeks</p> 
        <div>A computer science portal for geeks</div> 
    </body> 
</html>                     

Output:
percentage unit

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