Centring an element on a page

There are no doubt multiple ways of centring an element on a page using CSS, but here I present 2 different techniques that are straightforward and easy to implement. You could use these techniques for centring a login box, or an information message, etc. in the middle of a page.

Vertically and Horizontally Centred divs

Implementation

To center a couple of divs, I've defined them on the page as follows:

<div class="centered1">I am centered div 1.</div>
<div class="centered2">I am centered div 2.</div>

There's nothing special about these divs apart from they have the classes centered1 and centered2 respectively.

Technique 1

The class .centered1 uses an absolute position for the div and sets it to display 50% from the top and 50% from the left of the page. The margin of the div is then set to margin: -200px 0 0 -250px;. Since the div is 500px across and 400px wide, this margin has the effect of moving the div 250px left and 200px up, making it display in the center of the page.

.centered1 {
    position: absolute;
    width: 500px;
    height: 400px;
    top: 50%;
    left: 50%;
    background-color: goldenrod;
    margin: -200px 0 0 -250px;
}

Technique 2

The second technique is almost the same as the first, but this time I haven't used the margin to position the div in the middle of the page.

As previously, I've set the position to absolute and given the div a width and height. I've set the top and left properties to 50% to move the top left corner of the div to the centre of the screen.

Finally, I use a transformation to move the center of the div to be on the center of the page. transform: translate(-50%, -50%);. Again, the result is that the component is displayed in the center of the screen.

.centered2 {
    position: absolute;
    width: 300px;
    height: 200px;
    top: 50%;
    left: 50%;
    background-color: red;
    transform: translate(-50%, -50%);
}

Further Thoughts

Here, I've shown two simple techniques. I could probably have created the same effect using FlexBox or a Grid layout, or probably a number of other ways. If there are any different techniques that you use, please leave a comment below.

Credits

Photo by Mike Lewis HeadSmart Media on Unsplash

Doobries Domain - A blog by David Salter