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CSS CSS Basics (2014) Understanding Values and Units Em Units

Posted by Maddie Duffy
Maddie Duffy
3,659 Points

main header

If the main header font size is set at 2 ems then why is it displaying bigger than 32px?

2 Answers

Aakash Srivastava
Aakash Srivastava
5,415 Points
Aakash Srivastava
Aakash Srivastava
5,415 Points

Hey Maddie Duffy , em unit is relative unit .
Now , if main header font size is set at 2 ems , then it will displaying 32 px only when the font-size of body(which is parent of main header) is set to 1 em or 16 px .
Let's look at an example: 

body{
font-size: 1em;        // it is 16 px
}

.main-header{
font-size: 2em;       //  it will be 32 px  ( 16 * 2 )
}

Take another case : 

body{
font-size: 2em;     // // it is 32 px
}

.main-header{
font-size: 2em;       //  it will be 64px  ( 32 * 2 )
}

Hope it helped :)

Maddie Duffy
Maddie Duffy
3,659 Points

Thank you!!! Helped a lot!

Jonathan Grieve
MOD
Jonathan Grieve
Treehouse Moderator 91,252 Points
Jonathan Grieve
Jonathan Grieve
Treehouse Moderator 91,252 Points

The em unit is a relative unit. So it's probably displaying a size that is relative to its parent element.

"Relative length units are relative to other length values. "

So it 1 em is the equivalent of 16 pixels then 2 em will be 32 pixels.