CSS grid-auto-columns Property


The grid-auto-columns property sets the size of implicitly created columns in the layout grid container. This property only affects columns whose size is not explicitly set. In order to set the size of implicitly created rows in the layout grid container, you can use the grid-auto-rows property.

Initial value
Applies to
Grid containers
Computed value
tThe percentage as specified or the absolute length
JavaScript syntax

Interactive Demo



grid-auto-columns: <track-size>+
<track-size> = <track-breadth> | minmax( <inflexible-breadth> , <track-breadth> ) | fit-content( [ <length> | <percentage> ] )
<track-breadth> = <length-percentage> | <flex> | min-content | max-content | auto
<inflexible-breadth> = <length> | <percentage> | min-content | max-content | auto
<length-percentage> = <length> | <percentage>


  • autoThe size of the columns is determined by the size of the container and the size of the contents of the elements in the column. As a maximum, it is identical to the value of max-content , but at least it represents the largest minimum size. Automatic column sizes can be stretched using align-content properties and justify-content. This is the default value.
  • length / percentageSpecifies the size of implicitly created columns using a valid length value, or a percentage value. The value must be positive.
  • flexNon-negative value in "flexible" units of measure fr ( fractional unit ). Each implicitly created column occupies a part of the remaining space in the container of the layout grid in proportion to the specified coefficient. For example, when using the value 1fr 2fr , implicitly created columns will occupy ⅓ and ⅔ of the remaining space, respectively. The total size of such rows or columns is subtracted from the available space, which gives the remaining space, which is then divided between the rows and columns of flexible size in proportion to their coefficient. Values ​​between 0fr and 1fr have somewhat special behaviour, when the sum of the coefficients is less than 1, they will occupy less than 100% of the remaining space. When the available space is infinite (the width or height of the layout grid container is undefined), the size of the flexible grid columns is determined by their contents while maintaining the appropriate proportions.
  • max-contentA keyword that sets the size of each column based on the largest item in the column.
  • min-contentA keyword that sets the size of each column based on the smallest item in the column.
  • minmax (min, max)Functional notation that defines a range of sizes greater than or equal to min and less than or equal to max . If max is less than min , then max is ignored, and the function is treated as min . The value in "flexible" units of measurement as the maximum value sets the coefficient of flexibility of the column, this is not acceptable for determining the minimum.
  • fit-content (length | percentage)This is the formula min (max-content, max (auto, argument)) , which is calculated by analogy with auto (that is, minmax (auto, max-content) ), except that the size of the column is clamped by the argument value, if it is larger than the automatic minimum.


<div class="grid-container">
<div class = "item-a">A</div>
<div class="item-b">B</div>
<div class="grid-container2">
<div class="item-a">A</div>
<div class="item-b">B</div>
.grid-container2 {
   display: grid; 
   margin-top: 5px; 
   padding: 10px; 
   background: rgb(0,150,208); 
.grid-container > div,
.grid-container2 > div { 
   background: rgb(241,101,41);
   border: 1px solid #000; 
   text-align: center; 
   padding: 20px 0; 
.grid-container {
   grid-template-columns: 25px 100px;
   grid-auto-columns: 100px; 
.grid-container2 {
   grid-template-columns: 1fr 1fr;
   grid-auto-columns: 2fr;
.item-a {
   grid-column: 3 / 4; 
   grid-row: 2 / 3; 
   background: red !important; 
.item-b {
   grid-column: 4 / 5; 
   grid-row: 2 / 3; 
   background: yellow !important; 

Browser Support

The following table will show you the current browser support for the CSS grid-auto-columns property.

Edge Chrome Firefox Opera Safari
Tablets / Mobile
Chrome Firefox Opera Safari Samsung Webview

Last updated by CSSPortal on: 2nd January 2024