scrollbar-gutter

The scrollbar-gutter CSS property allows authors to reserve space for the scrollbar, preventing unwanted layout changes as the content grows while also avoiding unnecessary visuals when scrolling isn't needed.

An element's scrollbar gutter is the space between the inner border edge and the outer padding edge, where the browser may display a scrollbar. If no scrollbar is present, the gutter will be painted as an extension of the padding.

The browser determines whether classic scrollbars or overlay scrollbars are used:

Classic scrollbars are always placed in a gutter, consuming space when present.
Overlay scrollbars are placed over the content, not in a gutter, and are usually partially transparent.

Syntax

/* Initial value */
scrollbar-gutter: auto;

/* "stable" keyword, with optional modifier */
scrollbar-gutter: stable;
scrollbar-gutter: stable both-edges;

/* Global values */
scrollbar-gutter: inherit;
scrollbar-gutter: initial;
scrollbar-gutter: revert;
scrollbar-gutter: revert-layer;
scrollbar-gutter: unset;

Values

auto: The initial value. Classic scrollbars create a gutter when overflow is scroll, or when overflow is auto and the box is overflowing. Overlay scrollbars do not consume space.
stable: When using classic scrollbars, the gutter will be present if overflow is auto, scroll, or hidden even if the box is not overflowing. When using overlay scrollbars, the gutter will not be present.
both-edges: If a gutter would be present on one of the inline start/end edges of the box, another will be present on the opposite edge as well.

Formal definition

Initial value	auto
Applies to	scroll containers
Inherited	no
Computed value	specified keyword(s)
Animation type	discrete

Formal syntax

auto | stable && both-edges?

Examples

The examples below show how the different values for the scrollbar-gutter property would affect a scrollable div element (.container) with one or more paragraphs contained within.

Note: In the images for the examples, the user's system settings are set to classic scrollbars (always shown).

Example 1

Prevent unneeded layout changes as the content growing or shrinking causes the scrollbar to appear/disappear, a space is reserved for it.

.container {
  scrollbar-gutter: stable;
}

A containing div element with a paragraph of text inside and a space to the right where the scrollbar is

Example 2

Add symmetric spacing to both sides of the box so the content is centered:

.container {
  scrollbar-gutter: stable both-edges;
}

A containing div element with a paragraph of text inside, a space to the right where the scrollbar is and a matching empty space to the left

Example 3

Align the contents of a non-scrolling element and a scrolling one adjacent to it: This example shows two divs side by side. The one on the left has no scroll, but the one on the right does. Both have scrollbar-gutter applied, which also reserves space for the div on the left which doesn't have scrollable content. This is a good technique to use to keep the width of content consistent.

.container1 {
  overflow: hidden;
  scrollbar-gutter: stable;
}

.container2 {
  scrollbar-gutter: stable;
}

Two adjacent divs containing text, both with space for a scrollbar

Overlay scrollbars

For reference, this image shows the same div as above, but with the user's system settings set to overlay scrollbars. Note here the scrollbar will only show when the user is scrolling and on top of the content, so no space is reserved for it and the scrollbar-gutter property has no effect.

One div with text, no visible scrollbar

css properties scrollbar-gutter