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

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


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

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

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

/* Global values */
max-inline-size: inherit;
max-inline-size: initial;
max-inline-size: unset;


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

Formal definition

Initial value0
Applies tosame as width and height
Percentagesinline-size of containing block
Computed valuesame as max-width and max-height
Animation typea length, percentage or calc();

Formal syntax



Setting maximum inline size in pixels


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


.exampleText {
  writing-mode: vertical-rl;
  background-color: yellow;
  block-size: 100%;
  max-inline-size: 200px;



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

Browser compatibility

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See also