Flexbox Generator

CSS Flexbox — short for the Flexible Box Layout Module — is a one-dimensional layout system built into all modern browsers. It lets you arrange items along a single axis (either a row or a column), distribute space between them automatically, and align them along both the main axis and the cross axis without floating, clearing floats, or calculating pixel offsets. Since its standardization in 2012 and widespread browser adoption by 2015, Flexbox has become the default tool for building navigation bars, card rows, form controls, toolbars, and any layout where items need to share space intelligently.

The Flexbox Generator on this page gives you a real-time, visual way to configure every core Flexbox container property. Choose your direction, wrapping behavior, justification, and alignment using the dropdown controls, set a gap in pixels, and the preview panel updates instantly. When you're happy with the result, copy the generated CSS or Tailwind utility classes directly into your project.

Unlike CSS Grid — which controls both rows and columns simultaneously — Flexbox focuses on one axis at a time. This makes it ideal for components: button groups, navigation links, icon-and-label pairs, tag clouds, and any situation where items should flow naturally in one direction and you want fine control over spacing and alignment. Use the flex-direction property to switch between a horizontal row and a vertical column arrangement. Flexbox adapts to content size by default, which means items shrink and grow to fill the available space without breakpoints.

Every Flexbox layout starts with a flex container: an element with display: flex applied to it. All direct children automatically become flex items and are positioned according to the container's Flexbox properties. The generator produces the CSS for the container — you apply this CSS to the parent element in your stylesheet, and the children respond automatically.

The Flexbox Generator collects your chosen settings and assembles a complete, ready-to-paste CSS rule block. Every property is written explicitly so the output works without relying on inherited or default browser values. The generator also produces a Tailwind CSS equivalent for projects built with the utility-class framework.

The generated CSS block assembles six properties in the following structure:

For projects using Tailwind CSS, the generator computes a utility-class equivalent alongside the raw CSS output. Tailwind's flex utilities map directly to Flexbox properties, though with some approximations that are worth understanding.

The Tailwind output is built by combining several utility classes:

• flex — sets display: flex
• flex-col — added when flex-direction is column
• flex-wrap — added when flex-wrap is wrap
• justify-{value} — maps justify-content (e.g. justify-center, justify-between)
• items-{value} — maps align-items (e.g. items-center, items-stretch)
• gap-{Math.round(gap / 4)} — converts the pixel gap to Tailwind spacing units

The gap conversion is straightforward: Tailwind's spacing scale uses 4px increments, so the generator divides your pixel gap by 4 and rounds to the nearest integer. A gap of 16px becomes gap-4 (16 ÷ 4 = 4). A gap of 20px becomes gap-5 (Math.round(20 / 4) = 5). A gap of 12px becomes gap-3 (12 ÷ 4 = 3).

The Tailwind output is a useful starting point but represents a simplified version. Some values — like row-reverse or wrap-reverse — may not have direct Tailwind class equivalents and require custom CSS or Tailwind's arbitrary-value syntax. The raw CSS output is always the authoritative result; the Tailwind classes are a convenience for quickly wiring up a layout in a utility-class project.

The live preview panel shows numbered boxes rendered with the exact CSS values you've selected. Changing any control instantly updates both the preview and the code output so you can verify the layout looks correct before copying it.

flex-direction is the most fundamental Flexbox property because it determines which axis items flow along and which direction they go. The four options available in the generator cover every orientation:

flex-wrap controls what happens when items overflow the main axis. By default, nowrap forces all items onto a single line — items will shrink to fit if necessary. Setting wrap allows items to break onto additional lines when the container is too narrow. wrap-reverse wraps items onto new lines in the opposite cross-axis direction, so new lines appear above the previous ones instead of below.

When flex-wrap: wrap is active, the container becomes multi-line and align-content becomes relevant. It controls how the wrapped lines themselves are distributed along the cross axis — similar to how justify-content distributes items along the main axis. If you only have one line, align-content has no visible effect regardless of its value.

Common use cases for wrapping include responsive tag clouds, image galleries, and navigation links that should reflow on small screens. Setting flex-wrap: wrap with a fixed item width (applied to the child elements) gives you a fluid grid-like layout without needing CSS Grid.

Flexbox provides three distinct alignment properties that operate at different levels. Confusing them is one of the most common Flexbox mistakes; understanding the distinction will help you get the layout you want on the first try.

justify-content controls how items are distributed along the main axis. In a row direction, this means horizontal positioning; in a column direction, it means vertical positioning. The six options in the generator produce these behaviors:

• flex-start — items packed to the start of the main axis (left for rows)
• flex-end — items packed to the end (right for rows)
• center — items centered on the main axis
• space-between — first item at start, last item at end, equal gaps between
• space-around — equal space around each item (half-size gaps at the edges)
• space-evenly — equal space between items AND at the edges

align-items controls how items are aligned along the cross axis (the axis perpendicular to flex-direction). For a row layout, this is the vertical axis. For a column layout, it is the horizontal axis. The stretch default makes items fill the full cross-axis size of the container. center is the classic "vertically center an element" solution that was difficult before Flexbox. baseline aligns items so that their text baselines line up, which is useful for mixed font-size labels or icon-and-text pairs.

align-content only applies when flex-wrap: wrap is active and there are two or more lines of items. It distributes the lines themselves along the cross axis, similar to how justify-content distributes items along the main axis. When all items fit on one line, align-content has no visible effect regardless of the selected value.

The gap property sets uniform spacing between all flex items. Unlike margins, gap is never added before the first item or after the last — only between items. This makes it far more reliable than manually applying margin to every item and then removing the margin from the first or last one. The generator accepts gap values from 0 to 64px using the slider control.

The Flexbox Generator includes four quick-preset buttons that produce the most commonly needed layout configurations. Understanding what each one does helps you adapt them to your project's needs.

Center All sets flex-direction: row, justify-content: center, and align-items: center. This is the classic solution for centering content both horizontally and vertically inside a container — a long-standing pain point that Flexbox solved elegantly. Apply this to a full-height container and any content inside it will be perfectly centered.

Space Between sets flex-direction: row, justify-content: space-between, and align-items: center. This is the standard navigation bar pattern: a logo on the far left, navigation links on the far right, with all items vertically centered. It works equally well for card rows where you want items pushed to opposite ends of a container.

Vertical Stack sets flex-direction: column, justify-content: flex-start, and align-items: stretch. This is the sidebar or form layout pattern where elements stack top to bottom and each one fills the full width of the container. Combined with a set height and justify-content: space-between, this can also distribute items evenly in a vertical layout.

Wrap Grid sets flex-direction: row and flex-wrap: wrap. When child elements have a fixed or percentage width applied (e.g. width: calc(33.33% - gap)), this produces a flowing grid-like layout without CSS Grid. It is especially useful for tag lists, badge groups, and image thumbnails that should reflow naturally on smaller screens.

Beyond these presets, Flexbox is ideal for media objects (an image beside a block of text), button groups, and any horizontal toolbar where item widths vary but spacing should remain consistent. The gap property makes maintaining consistent spacing trivial compared to margin-based approaches.