CSS Grid and CSS Flexbox are the most well-known and widely used web layout technologies, and they’ve been hot topics over the past few years. However, despite some surface similarities, they’re actually used for very different tasks—each solves a distinct set of problems, often the kinds the other cannot. You’ve likely noticed yourself that different projects require different layout systems.
Still, many developers wonder: when should you use which? More specifically—when is Flexbox better, and when should you choose Grid? Can one replace the other? In reality, it’s not hard to figure out, but we decided to take a closer look at these questions and highlight a few nuances of both technologies.
Grid or Flexbox?
It’s a common question, but here’s the simple truth: you need to learn both and test them in practice. Over time, any web developer will naturally begin to understand which is best for specific components in a given project. There’s no universal rule like: “Follow your instincts and choose whichever feels more comfortable or technically convenient.” Grid Layout and Flexbox are both CSS. It doesn’t matter if you write display: grid or display: flex—you’re still working within the same CSS system. That’s because both are based on the rules of CSS Intrinsic and Extrinsic Sizing and the Box Alignment specifications.
In previous posts, we’ve discussed why developers choose different frameworks like React, Foundation, Vue, etc. But those are large-scale tools. Grids are different. They’re part of CSS, which is used to control each and every visual element on the page. So logically, both Grid and Flexbox can be used—as long as they meet the layout requirements. Some designers don’t use Flex or Grid exclusively but build container grids with nested grids that act as flex items. That’s perfectly valid when layout or design needs call for it—mixing strict two-dimensional grid structure with flexible flex parts.
Flexbox in Practice
Think of it like this: why do we need a car when we have a bicycle? It’s all about what each tool can do. Flexbox—described in the MDN glossary—is about alignment and distribution. So if your page has many items, and on mobile or small screens these elements need to rearrange, then Flexbox is your go-to. It distributes space so that larger items get more room and smaller ones get less, making everything easier to read and navigate.
In other words, Flexbox is perfect for building responsive layouts where elements don’t have fixed sizes and don't need rigid placement. It's for situations where the developer just needs to "lay everything out next to each other." For instance, if you need a fluid grid with adjustable widths and a clear row-based structure—you could approach it with Grid (which will fill cells automatically) or with Flex (which will dynamically fill those same cells). Different approaches, different results.
In the first example, text blocks are placed in strict grid cells. The number of columns doesn’t change, but row height varies depending on content. In this setup, if there are empty cells with auto-flow, you can’t really control row length.
In the second example, which uses Flexbox, items expand to fill all available space, so there’s no fixed alignment or positioning.
But you can modify the second example by setting flex-basis to auto. Then text won’t wrap to new lines, and cell width adapts to the full text length—while still fitting within the container width.
But examples are one thing, real-world use is another. Think about how often we see tag clouds—short keywords placed below posts or in sidebars. They look "random" and don’t follow any strict layout. This is exactly where Flexbox works best. It fills all available space and lines up elements on a row. No need for grid alignment here—grids are for rows and columns. Tags are chaotic by nature.
But in this demo, Flex handles it beautifully. Even with different word lengths, the tag cloud looks clean, structured, and neat.
Another Flex use case: perfectly centering content inside an element—text, icons, images, etc. The idea is vertical and horizontal centering.
In the future (once browsers support full Box Alignment properties), we’ll be able to achieve this without even needing display: flex. But for now, that line of CSS is essential—and it was used in all the above examples.
What Else Is Flexbox Good For?
Forms. More precisely— keeping a form from falling apart when the page width changes. Groups of icons, fields, small blocks, and buttons can all be laid out and aligned cleanly, without complicated coordinate math or axis positioning. And yes, the field sizes will adapt to the form width too.
Another Flex feature: dynamic expansion of a single item while others remain at their original size. See this example in two versions—default and with the middle block expanded due to added content.
To summarize: Flexbox is ideal for small layout cases, especially when things need to be aligned not just by axis but to fill space logically—while still being readable and visually balanced. It’s also helpful when you later need to insert new content into a finished design—Flex is often more forgiving than Grid for this.
Grid is a two-dimensional layout system. When a row overflows with items, it creates a new row. But that’s often inconvenient. Flex, on the other hand, can compress the row and fit new items by setting flex-basis to auto or 0.
Here are a few sites using Flexbox and Grid in action: The Guardian, news layouts, hexagon menu, and magazine blocks.
Grid Has Its Place Too
Despite how useful Flexbox is, there are layouts where Grid is clearly the better tool. One example we already saw—when all items are placed in strict cell positions like a table.
The point is—Flex works in one direction. It creates a linear row that wraps. Grid builds layouts from both rows and columns, with each element assigned to a cell. That’s why Grid CSS is best when items need to be in strict, fixed positions regardless of size.
Some web developers think Flexbox is only for components, and Grid is for full-page layout. But that’s not quite true. Sometimes you have just 2–3 elements that need precise structure—and in that case, Flex may be unnecessary overhead.
Another reason to prefer Grid: when you have multiple dynamic containers that should be placed next to or below one another. Grid can strictly define that. Or you can use Grid to limit Flex’s dynamic resizing if needed. It all depends on the layout structure—but this trick is often very practical.
Some developers even simulate static grid-like layouts using Flexbox, with flex-grow: 0 and fixed percentages. But isn’t that exactly what Grid was built for? Here’s an example of a table built using Flexbox. Once you expand one element, the entire layout breaks. If layout rigidity was the goal, Flex just wasn’t the right tool.
Conclusion
Even though it’s fairly easy to explain and understand how Grid Layout differs from Flexbox, choosing which one to use in the moment isn’t always clear-cut. The best approach is still to try both. You can use Grid and Flex together or switch between them based on layout needs.
We’ve tried to show how alignment and sizing logic works with dynamic elements, and how static structure impacts that. CSS Grid and Flexbox were made for different problems, and Grid is still less supported by browsers than Flexbox. But support is growing, and we’ll soon be able to use both technologies even more freely. You can already do that today—if your site targets modern browsers.