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The line-height-step CSS property defines the step units for line box heights. When the step unit is positive, line box heights are rounded up to the closest multiple of the unit. Negative values are invalid.

/* Keyword values */
line-height-step: none;

/* Point values */
line-height-step: 18pt;

Initial valuenone
Applies toblock container elements
Computed valuean absolute length; if the keyword none is specified, the computed value is 0
Animation typediscrete
Canonical orderper grammar


The line-height-step property is specified as any one of the following:


No value is given.
The specified <length> is used in the calculation of the line box height step.

Formal syntax

none | <length>


In the following example, the height of line box in each paragraph is rounded up to the step unit. The line box in <h1> does not fit into one step unit and thus occupies two, but it is still centered within the two step unit. 

:root {
  font-size: 12pt;
  --my-grid: 18pt;
  line-height-step: var(--my-grid);
h1 {
  font-size: 20pt;
  margin-top: calc(2 * var(--my-grid));

The result of these rules are shown below.

How the line-height-step property affects the appearance of text.


Specification Status Comment
CSS Rhythmic Sizing
The definition of 'line-height-step' in that specification.
Working Draft Initial definition.

Browser compatibility

Feature Chrome Edge Firefox (Gecko) Internet Explorer Opera Safari
Basic support 59 ? ? ? 47 ?
Feature Android Webview Chrome for Android Edge Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile
Basic support 59 59 ? ? ? 47 ?


See also

Document Tags and Contributors

 Contributors to this page: Siilwyn, jpmedley
 Last updated by: Siilwyn,