The inset-block CSS property defines the logical block start and end offsets of an element, which maps to physical offsets depending on the element's writing mode, directionality, and text orientation. It corresponds to the top and bottom, or right and left properties depending on the values defined for writing-mode, direction, and text-orientation.

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Constituent properties

This property is a shorthand for the following CSS properties:


/* <length> values */
inset-block: 3px 10px;
inset-block: 2.4em 3em;
inset-block: 10px; /* value applied to start and end */

/* <percentage>s of the width or height of the containing block */
inset-block: 10% 5%;

/* Keyword value */
inset-block: auto;

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


The inset-block property takes the same values as the left property.

Formal definition

Initial valueas each of the properties of the shorthand:
Applies topositioned elements
Percentageslogical-height of containing block
Computed valueas each of the properties of the shorthand:
Animation typea length, percentage or calc();

Formal syntax

inset-block = 


Setting block start and end offsets


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


div {
  background-color: yellow;
  width: 120px;
  height: 120px;

.exampleText {
  writing-mode: vertical-lr;
  position: relative;
  inset-block: 20px 50px;
  background-color: #c8c800;



CSS Logical Properties and Values Level 1
# propdef-inset-block

Browser compatibility

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See also