Using calc() in CSS responsive design

tyzia profile image Andrei Navumau Updated on ・2 min read

How to use calc() in css styling

Last time I made a post about my struggle with responsive design and adding multiple breakpoints and doing a lot of math in excel. The post can be found here. Thanks to ArcCosine's comment, I learned about calc() function in CSS. I applied it in my css file and it worked like a charm!

Here is the html code:

div id=A

    div id=B


In browser this looks like this:

div in browser

To keep it short: I have 5 images of social icons, 51px fixed width each. The width of their container (div id=B) is 480px. I would like to calculate margin between icons responsive to screen size. So my css calculation is like this:

#B img {
    margin-right: calc((100% - 255px) / 4);

#B img:last-child {

Just a tiny explanation:

  1. We take 100% of the width of the icon's container. It's 480px.
  2. Then we deduct the width of all icons, which is 5*51px = 255px.
  3. This gives us the remaining spacing in the container. We need to divide it by 4. Because we have 4 gaps between 5 images.
  4. So we have the length of our margin-right. Last icon's margin we set to zero.

Now, if we resize the screen, container's width will be, for instance, 460px and margin-right will be recalculated based on the new container's width.

That short, that simple. Thank you ArcCosine, once again.

Posted on Dec 7 '17 by:

tyzia profile

Andrei Navumau


I am a Web Developer


markdown guide

Another way of positioning these in a responsive manner would be flexbox in combination with margins:


Thank you, morefox. Flex - is a completely new thing for me, but I have already tried it out and I love, how simple is to code with flex.


there are also frameworks such as bulma.io and bootstrap v4 also uses flexbox, a tool that has been long awaited by frontend devs for solving the most simple layout and grid problems


and not worry about calculating margins