`min-block-size` CSS property

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

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

min-block-size: 150px;
writing-mode: horizontal-tb;

min-block-size: 150px;
writing-mode: vertical-rl;

min-block-size: 20px;
writing-mode: horizontal-tb;

min-block-size: 15em;
writing-mode: vertical-lr;

<section class="default-example" id="default-example">
  <div class="transition-all" id="example-element">
    This is a box where you can change the minimum block size. <br />If there is
    more content than the minimum the box will grow in the block dimension as
    needed by the content.
  </div>
</section>

#example-element {
  display: flex;
  flex-direction: column;
  background-color: #5b6dcd;
  justify-content: center;
  color: white;
}

Syntax

/* <length> values */
min-block-size: 100px;
min-block-size: 5em;
min-block-size: anchor-size(self-inline);

/* <percentage> values */
min-block-size: 10%;

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

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

Values

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

Formal definition

Formal syntax

Examples

Setting minimum block size for vertical text

HTML

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

CSS

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

Result

Specifications

Browser compatibility

See also

• The mapped physical properties: min-width and min-height
• writing-mode