If the goal is to create a grid with equal height rows, where the tallest cell in the grid sets the height for all rows, here’s a quick and simple solution:
- Set the container to
How it works
Grid Layout provides a unit for establishing flexible lengths in a grid container. This is the
fr unit. It is designed to distribute free space in the container and is somewhat analogous to the
flex-grow property in flexbox.
If you set all rows in a grid container to
1fr, let’s say like this:
… then all rows will be equal height.
It doesn’t really make sense off-the-bat because
fr is supposed to distribute free space. And if several rows have content with different heights, then when the space is distributed, some rows would be proportionally smaller and taller.
Except, buried deep in the grid spec is this little nugget:
7.2.3. Flexible Lengths: the
When the available space is infinite (which happens when the grid container’s width or height is indefinite), flex-sized (
fr) grid tracks are sized to their contents while retaining their respective proportions.
The used size of each flex-sized grid track is computed by determining the
max-contentsize of each flex-sized grid track and dividing that size by the respective flex factor to determine a “hypothetical
The maximum of those is used as the resolved
1frlength (the flex fraction), which is then multiplied by each grid track’s flex factor to determine its final size.
So, if I’m reading this correctly, when dealing with a dynamically-sized grid (e.g., the height is indefinite), grid tracks (rows, in this case) are sized to their contents.
The height of each row is determined by the tallest (
max-content) grid item.
The maximum height of those rows becomes the length of
1fr creates equal height rows in a grid container.
Why flexbox isn’t an option
As noted in the question, equal height rows are not possible with flexbox.
Flex items can be equal height on the same row, but not across multiple rows.
This behavior is defined in the flexbox spec:
In a multi-line flex container, the cross size of each line is the minimum size necessary to contain the flex items on the line.
In other words, when there are multiple lines in a row-based flex container, the height of each line (the “cross size”) is the minimum height necessary to contain the flex items on the line.