CSS gap

The CSS gap property is shorthand for the column-gap and row-gap properties.

It specifies spacing between columns and rows in flexbox containers and grid containers, and columns in multi-column containers.

You can specify the gap to be either normal or to be a specific size (for example, a value of 30px would create a gap of 30 pixels).

Multi-Column Layout

Here's an example of gap being used on a multi-column container.

Flexbox Layout

Here's an example of gap being used on a flex container.

Grid Layout

Here's an example of gap being used on a grid container (this is the same example that's displayed at the top of this article).


This means that the first value provides the row-gap, and the second provides the column-gap.

If 'row-gap' is omitted, it's set to the same value as 'column-gap'.

Possible Values

Here are the values that are accepted for each argument.


Specifies the width of the gap. For example, 40px would create a column gap of 40 pixels. Cannot be a negative value.

Note that <length-percentage> is equivalent to [ <length> | <percentage> ]. In other words, you can provide a <length> or <percentage> value.

Represents a used value of 1em on multi-column containers, and a used value of 0px in all other contexts.

In addition, all CSS properties also accept the following CSS-wide keyword values as the sole component of their property value:

Represents the value specified as the property's initial value.
Represents the computed value of the property on the element's parent.
This value acts as either inherit or initial, depending on whether the property is inherited or not. In other words, it sets all properties to their parent value if they are inheritable or to their initial value if not inheritable.

Basic Property Information

Initial Value
See individual properties (row-gap and column-gap)
Applies To
Multi-column containers, flex containers, grid containers.
Yes, by computed value type (see example)

History of gap & grid-gap

The CSS Grid Layout module was originally written with its own set of gutter properties (grid-gap, grid-column-gap, and grid-row-gap). Those properties were later unified into the gap/row-gap/column-gap naming, which also expanded the scope to include flexbox containers, grid containers and multi-column containers.

For compatibility purposes, those grid-* property names are now aliases for the properties with the new names.


CSS Specifications

The gap property is defined in CSS Box Alignment Module Level 3 (W3C Working Draft, 21 April 2020).

Vendor Prefixes

For maximum browser compatibility many web developers add browser-specific properties by using extensions such as -webkit- for Safari, Google Chrome, and Opera (newer versions), -ms- for Internet Explorer, -moz- for Firefox, -o- for older versions of Opera etc. As with any CSS property, if a browser doesn't support a proprietary extension, it will simply ignore it.

This practice is not recommended by the W3C, however in many cases, the only way you can test a property is to include the CSS extension that is compatible with your browser.

The major browser manufacturers generally strive to adhere to the W3C specifications, and when they support a non-prefixed property, they typically remove the prefixed version. Also, W3C advises vendors to remove their prefixes for properties that reach Candidate Recommendation status.

Many developers use Autoprefixer, which is a postprocessor for CSS. Autoprefixer automatically adds vendor prefixes to your CSS so that you don't need to. It also removes old, unnecessary prefixes from your CSS.

You can also use Autoprefixer with preprocessors such as Less and Sass.