Items
.container
1grow·0 shrink·1
2grow·0 shrink·1
3grow·0 shrink·1
/* Container */
.container {
  display: flex;
  gap: 8px;
  padding: 16px;
  min-height: 160px;
}

CSS Flexbox Generator — Visual Flexbox Layout Builder

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About this tool

Free Visual CSS Flexbox Builder

CSS Flexbox Builder is a visual layout editor that gives you interactive controls for every flex container and flex item property, with a live preview that updates instantly as you make changes. CSS Flexbox (Flexible Box Layout Module, Level 1) is the standard one-dimensional layout model used in virtually every modern web project — from navigation bars and button groups to responsive card grids and centered hero sections. The flex model has two layers: the container (which sets flex-direction, flex-wrap, justify-content, align-items, align-content, and gap) and the individual items (which each have flex-grow, flex-shrink, flex-basis, order, and align-self). Memorizing all combinations is difficult; this tool lets you manipulate them visually and immediately see what each property does. Once you have the layout you need, export it as clean CSS with a comment-annotated rule block, SCSS with nesting, Tailwind utility classes ready to paste into className, or a React inline styles object. Add or remove flex items dynamically in the preview to see how the container handles different numbers of children.

Features

  • Container controls — flex-direction, flex-wrap, justify-content, align-items, align-content, gap
  • Per-item controls — flex-grow, flex-shrink, flex-basis, order, align-self
  • Add and remove flex items dynamically in the live preview
  • Live preview updates in real time with every property change
  • Export as CSS rule block, SCSS nesting, Tailwind utility classes, or React style object
  • Tooltip on every property label explaining what the property does
  • Reset to defaults in one click
  • 100% browser-based — no data sent to a server

How to Use

Use the Container panel on the left to configure your flex container. Set flex-direction to row (horizontal, the default) or column (vertical) using the dropdown. If you want items to wrap when the container is too narrow, set flex-wrap to "wrap". Use the justify-content dropdown to control how items are distributed along the main axis — "center" centers them, "space-between" spreads them to both edges, "space-around" adds equal space around each. Use align-items to control cross-axis alignment — "center" vertically centers items in a row container, "stretch" (default) makes items fill the container height. Add multiple flex items using the + button in the preview area, then click any item to select it and open its individual controls. For each item, set flex-grow to control how much it expands into available space, flex-shrink to control whether it can compress below its natural size, and flex-basis to set a starting size. Use the order input to reorder items visually without changing the HTML source. align-self overrides the container's align-items for that one item. The live preview reflects every change immediately. Switch between the CSS, SCSS, Tailwind, and React export tabs at the bottom right and click Copy.

Common Use Cases

▦
Learning Flexbox
Flexbox is one of the most important CSS layout tools, but the interaction between justify-content, align-items, and flex-grow can be confusing without visual feedback. This builder lets you experiment with every combination in real time, making it the fastest way to build an intuitive mental model of how flex containers behave.
⊞
Navbar & Header Layouts
Navigation bars almost always use Flexbox: a row container with justify-content: space-between to push the logo left and the links right, align-items: center to vertically center everything, and gap for consistent spacing. Build and export the exact configuration for your navbar in seconds.
⇄
Card Grid & Responsive Rows
A flex container with flex-wrap: wrap and flex-basis on each card creates a responsive grid that reflows automatically at narrow widths without media queries. Set a fixed flex-basis (e.g. 280px) with flex-grow: 1 and cards fill available space, wrapping to the next line when they cannot fit.
✦
Centering Content
The classic Flexbox centering trick — display: flex; justify-content: center; align-items: center — centers any content both horizontally and vertically. This builder lets you generate that code instantly and see how it responds when you change the container's height or add more items.
≡
Design System Components
Use the Tailwind export to get the exact utility class combination for buttons, badges, form rows, and list items in your component library. The per-item controls generate individual item classes so you can handle the common case where one item should grow to fill remaining space.
◎
Interview & Study Preparation
Flexbox questions are common in frontend interviews and CSS assessments. Use this builder to visualize and memorize how each property behaves under different conditions — especially the counter-intuitive interactions between flex-shrink, flex-basis, and the container's cross-axis when items overflow.

Frequently Asked Questions

CSS Flexbox (Flexible Box Layout) is a one-dimensional layout model that lets you align and distribute space among items in a container along a single axis — either a row (horizontal) or a column (vertical). It solves classic layout problems like vertical centering, equal-height columns, and space distribution that were difficult with floats and positioned elements. Setting display: flex on a container makes all its direct children flex items that respond to flex properties.

The Flexbox Builder provides a visual interface for every flex container and flex item property. You control the container's flex-direction, flex-wrap, justify-content, align-items, and align-content through dropdowns, and set each item's flex-grow, flex-shrink, flex-basis, order, and align-self through individual controls. The layout preview updates live with every change, and the tool generates production-ready code in CSS, SCSS, Tailwind utility classes, or a React inline style object.

justify-content aligns flex items along the main axis — horizontally for flex-direction: row, vertically for flex-direction: column. It distributes space between items (space-between, space-around) or centers them (center). align-items aligns items along the cross axis (perpendicular to the main axis). In a row container, align-items controls vertical alignment; in a column container, it controls horizontal alignment. align-content does the same as align-items but for multiple lines when flex-wrap is enabled.

flex-grow defines how much a flex item grows relative to its siblings when there is extra space available in the container. A value of 1 means the item takes one proportional share of the free space. An item with flex-grow: 2 grows twice as wide (or tall, in a column) as items with flex-grow: 1. Setting flex-grow: 0 (default) means the item does not grow at all beyond its natural size.

flex-shrink controls how much a flex item shrinks when the container is smaller than the combined width of its items. The default value is 1, meaning all items shrink equally. Set flex-shrink: 0 on an item to prevent it from ever shrinking below its natural size — useful for fixed-width sidebars or images that should not distort. Higher values make an item shrink proportionally faster than siblings.

Flexbox is ideal for one-dimensional layouts — navbars, button groups, card rows, and centering content in either direction. Grid is best for two-dimensional layouts where you need to control both rows and columns simultaneously — page scaffolding, image galleries, and complex magazine layouts. In practice, most UIs use both: Grid for the overall page structure and Flexbox for the alignment within individual components.

flex-wrap controls whether flex items wrap onto multiple lines when there is not enough space. The default "nowrap" keeps all items on one line and allows them to overflow or shrink. "wrap" lets items move to a new row (or column) when they hit the container edge — this is how responsive card grids work. "wrap-reverse" wraps in the opposite direction.

Yes. The Tailwind tab generates the equivalent utility classes for your container configuration — for example flex flex-row justify-between items-center gap-4 — and per-item classes like grow, shrink-0, or self-end. You can copy these classes and paste them directly into your HTML or JSX className attribute without any additional configuration.