W3cubDocs

/CSS

block-size

The block-size CSS property defines the horizontal or vertical size of an element's block, depending on its writing mode. It corresponds to either the width or the height property, depending on the value of writing-mode.

If the writing mode is vertically oriented, the value of block-size relates to the width of the element; otherwise, it relates to the height of the element. A related property is inline-size, which defines the other dimension of the element.

Syntax

/* <length> values */
block-size: 300px;
block-size: 25em;

/* <percentage> values */
block-size: 75%;

/* Keyword values */
block-size: max-content;
block-size: min-content;
block-size: fit-content(20em);
block-size: auto;

/* Global values */
block-size: inherit;
block-size: initial;
block-size: unset;

Values

The block-size property takes the same values as the width and height properties.

Formal definition

Initial value auto
Applies to same as width and height
Inherited no
Percentages block-size of containing block
Computed value same as width and height
Animation type a length, percentage or calc();

Formal syntax

<'width'>

Examples

Block size with vertical text

HTML

<p class="exampleText">Example text</p>

CSS

.exampleText {
  writing-mode: vertical-rl;
  background-color: yellow;
  block-size: 200px;
}

Result

Specifications

Specification Status Comment
CSS Logical Properties and Values Level 1
The definition of 'block-size' in that specification.
Editor's Draft Initial definition

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
block-size 57 79 41
41
38 — 51
Disabled
Disabled From version 38 until version 51 (exclusive): this feature is behind the layout.css.vertical-text.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
No 44 12.1
fit-content 57 79 41
Prefixed
41
Prefixed
Prefixed Implemented with the vendor prefix: -moz-
No 44 12.1
max-content 57 79 66
66
41
Prefixed
Prefixed Implemented with the vendor prefix: -moz-
No 44 12.1
min-content 57 79 66
66
41
Prefixed
Prefixed Implemented with the vendor prefix: -moz-
No 44 12.1
Mobile
Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
block-size 57 57 41
41
38 — 51
Disabled
Disabled From version 38 until version 51 (exclusive): this feature is behind the layout.css.vertical-text.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.
43 12.2 5.0
fit-content 57 57 41
Prefixed
41
Prefixed
Prefixed Implemented with the vendor prefix: -moz-
43 12.2 5.0
5.0
Uses the non-standard name: -webkit-fill-available
max-content 57 57 66
66
41
Prefixed
Prefixed Implemented with the vendor prefix: -moz-
43 12.2 5.0
min-content 57 57 66
66
41
Prefixed
Prefixed Implemented with the vendor prefix: -moz-
43 12.2 5.0

See also

© 2005–2020 Mozilla and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/CSS/block-size