How to Center a Div Within Another Div

How can I center a div within another div?

You need to set the width of the container (auto won't work):

#container {
    width: 640px; /* Can be in percentage also. */
    height: auto;
    margin: 0 auto;
    padding: 10px;
    position: relative;
}

The CSS reference by MDN explains it all.

Check out these links:

• auto - CSS reference | MDN
• margin - CSS reference | MDN
• What is the meaning of auto value in a CSS property - Stack Overflow

In action at jsFiddle.

What is the best way to center a div inside another div?

Here's some ideas of how you can achieve it.

https://codepen.io/Warisara-L/pen/wOMxwR

// HTML
<div class="wrapper" id="solution-1">
  <div class="inner">1</div>
</div>

// SCSS
#solution-1 {
  display: grid;
  .inner {
    margin: auto;
  }
}

#solution-2 {
  display:flex;
  justify-content: center;
  align-items: center;
}

#solution-3 {
  position: relative;
  .inner {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
  }
}

#solution-4 {
  display: flex;
  .inner {
    margin: auto;
  }
}

#solution-5 {
  display: grid;
  justify-content: center;
  align-items: center;
}

#solution-6 {
  position: relative;
  .inner {
    position: absolute;
    margin: auto;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
  }
}

#solution-7 {
  height: 120px;
  line-height: 120px;
  text-align: center;
  .inner {
    display: inline-block;
    vertical-align: middle;
  }
}

#solution-8 {
  display: flex;
  .inner {
    align-self: center;
    margin: 0 auto;
  }
}

Have a good day sir :)

Vertically centering a div inside another div

tl;dr

Vertical align middle works, but you will have to use table-cell on your parent element and inline-block on the child.

This solution is not going to work in IE6 & 7.
Yours is the safer way to go for those.
But since you tagged your question with CSS3 and HTML5 I was thinking that you don't mind using a modern solution.

The classic solution (table layout)

This was my original answer. It still works fine and is the solution with the widest support. Table-layout will impact your rendering performance so I would suggest that you use one of the more modern solutions.

Here is an example

Tested in:

• FF3.5+
• FF4+
• Safari 5+
• Chrome 11+
• IE9+

HTML

<div class="cn"><div class="inner">your content</div></div>

CSS

.cn {
  display: table-cell;
  width: 500px;
  height: 500px;
  vertical-align: middle;
  text-align: center;
}

.inner {
  display: inline-block;
  width: 200px; height: 200px;
}

Modern solution (transform)

Since transforms are fairly well supported now there is an easier way to do it.

CSS

.cn {
  position: relative;
  width: 500px;
  height: 500px;
}

.inner {
  position: absolute;
  top: 50%; left: 50%;
  transform: translate(-50%,-50%);
  width: 200px;
  height: 200px;
}

Demo

♥ my favourite modern solution (flexbox)

I started to use flexbox more and more its also well supported now Its by far the easiest way.

CSS

.cn {
  display: flex;
  justify-content: center;
  align-items: center; 
}

Demo

More examples & possibilities:
Compare all the methods on one pages

How to center a div inside another div

If the two divs got fixed dimensions, you can simply put a margin on the second div. In your case :

#div2 {
 margin: 25px;
}

Or, if the divs got variable dimensions, try :

#div1 {
 position: relative;
}
#div2 {
position:absolute;
left:50%;
top:50%;

transform: translate(-50%,-50%);

}

OR :

#div1 {
text-align: center;

}
#div2 {
display: inline-block;
vertical-align: middle;

}

That's all the way I know to achieve that :)

Centering floating divs within another div

First, remove the float attribute on the inner divs. Then, put text-align: center on the main outer div. And for the inner divs,
use display: inline-block. Might also be wise to give them explicit widths too.

<div style="margin: auto 1.5em; display: inline-block;">
  <img title="Nadia Bjorlin" alt="Nadia Bjorlin" src="headshot.nadia.png"/>
  <br/>
  Nadia Bjorlin
</div>

How can I horizontally center an element?

You can apply this CSS to the inner <div>:

#inner {
  width: 50%;
  margin: 0 auto;
}

Of course, you don't have to set the width to 50%. Any width less than the containing <div> will work. The margin: 0 auto is what does the actual centering.

If you are targeting Internet Explorer 8 (and later), it might be better to have this instead:

#inner {
  display: table;
  margin: 0 auto;
}

It will make the inner element center horizontally and it works without setting a specific width.

Working example here:

#inner {
  display: table;
  margin: 0 auto;
  border: 1px solid black;
}

#outer {
  border: 1px solid red;
  width:100%
}

<div id="outer">
  <div id="inner">Foo foo</div>
</div>

.container { position: relative; width: 100px; /* not part of solution */ height: 100px; /* not part of solution */ background-color: #808; /* not part of solution */ border-radius: 50%; /* not part of solution */}.content { position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%); text-align: center; /* not part of solution */}

<div class="container">    <div class="content">I'm absolutly centered</div></div>