Is it possible to calculate the Viewport Width (vw) without scrollbar?

Question

As mentioned in the title, is it possible to calculate the vw without the scrollbars in css only?

For example, my screen has a width of 1920px. vw returns 1920px, great. But my actual body width is only something like 1903px.

Is there a way for me to retrieve the 1903px value with css only (not only for direct children of the body), or do I absolutely need JavaScript for this?

Answer 1

One way to do this is with calc. As far as i know, 100% is the width including scrollbars. So if you do:

body {
  width: calc(100vw - (100vw - 100%));
}

You get the 100vw minus the width of the scrollbar.

You can do this with height as well, if you want a square that's 50% of the viewport for example (minus 50% of the scollbar width)

.box {
  width: calc(50vw - ((100vw - 100%)/2))
  height: 0
  padding-bottom: calc(50vw - ((100vw - 100%)/2))
}