CSS Flexbox Generator with Live Preview
The CSS Flexbox Generator is a visual tool that builds Flexbox layouts for you without writing code from scratch. Click buttons and adjust controls to shape the container and its items, watch the layout update in real time, then copy clean CSS straight into your project.
Flexbox is one of the most powerful CSS layout systems, but properties like justify-content, align-items, and flex-wrap, plus per-item controls like flex-grow and align-self, take time to memorize. This generator lets you experiment visually and see the result instantly, so it suits beginners learning how each property behaves, developers prototyping a layout fast, and designers exploring options before handoff.
How to Use the Flexbox Generator
Configure the container
In the Container section, set the parent flex properties: flex-direction (row or column), flex-wrap, justify-content on the main axis, align-items on the cross axis, align-content for wrapped lines, and the row and column gap.
Manage the items
Use Add Item and Remove Item to set how many boxes you need, up to 12 in total. Click a colored chip, or click an item directly in the preview, to select the one you want to edit.
Customize the selected item
For the selected item, adjust order, flex-grow, flex-shrink, and flex-basis to control sizing, override the container with align-self, and set an explicit width, height, and padding. Style it visually with a background color and border-radius.
Copy the generated CSS
The CSS updates automatically and includes only the properties that differ from their defaults, keeping the output minimal. Press Copy to send the code to your clipboard, or Reset to return to four default items.
Features
Full Container Control
Set all six container properties — flex-direction, flex-wrap, justify-content, align-items, align-content, and gap — with labeled button groups that show the real CSS value.
Per-Item Flex Properties
Select any item to tune order, flex-grow, flex-shrink, flex-basis, and align-self independently of the container.
Visual Item Styling
Give each item a background color, border-radius, explicit width and height, and custom padding so the preview matches your design.
Live Preview
Every change updates instantly. The container is shown with a dashed border and each item gets its own color for easy identification.
Click-to-Select Items
Pick an item to edit by clicking its chip in the list or by clicking it directly inside the preview area.
Add or Remove Items
Build layouts with anywhere from one to twelve flex items and adjust the count at any time.
Clean Code Output
The generated CSS lists only non-default properties, grouping container rules under .container and per-item overrides under .item-N selectors.
Adjustable Container Size
Change the preview width by percentage and the height in pixels to simulate different viewports and test how the layout responds.
One-Click Copy
Copy the ready-to-use CSS to your clipboard with a single click, then paste it straight into your stylesheet.
Reset to Defaults
Restore everything in one click — four items, no custom properties, and a container at 100% width by 300px height.
Frequently Asked Questions
What is the difference between justify-content and align-items?
justify-content aligns items along the main axis — horizontal in a row, vertical in a column. align-items aligns items along the cross axis, the opposite direction. In a row layout, justify-content handles horizontal spacing while align-items handles vertical alignment.
How do I center a div with Flexbox?
On the container, set justify-content to center and align-items to center. That centers the items both horizontally and vertically. Pick those two values in the generator and the preview will center the items right away.
When does align-content take effect?
align-content only applies when flex-wrap is set to wrap (or wrap-reverse) and the items span multiple lines. It controls how those lines are distributed along the cross axis. With a single line it has no visible effect.
What is the difference between flex-grow and flex-basis?
flex-basis sets an item's initial size before space is distributed, while flex-grow decides how much of the leftover space it claims. An item with flex-basis: 100px and flex-grow: 1 starts at 100px and then expands to fill the available room.
What is the difference between Flexbox and CSS Grid?
Flexbox is a one-dimensional system that lays items out along a single axis — a row or a column — and is ideal for toolbars, navigation, and aligning items in a line. CSS Grid is two-dimensional and arranges items in rows and columns at once, making it better for full page layouts. This generator focuses on Flexbox.
Why doesn't the generated code include every property?
The generator outputs only properties that differ from their CSS defaults, which keeps the code clean and minimal. If flex-direction is left at row (the default), for example, it is omitted from the output.
Can I use the generated CSS directly in my project?
Yes. The CSS is production-ready — copy it and apply the class names (.container, .item-1, and so on) to your HTML. You can rename the selectors to match your own naming convention.
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