CSS Flexbox Generator — Visual Layout Tool With Live Preview
Set flex-direction, justify-content, align-items, flex-wrap, and gap, watch a real CSS preview update, then copy the vanilla CSS or Tailwind v4 utilities. Adjustable item count (1–12) and four presets. Free, no signup, 100% in your browser.
row
nowrap
flex-start
stretch
Range: 1–12 items.
.container {
display: flex;
flex-direction: row;
justify-content: flex-start;
align-items: stretch;
flex-wrap: nowrap;
gap: 12px;
}flex flex-row justify-start items-stretch flex-nowrap gap-3Full Flex Property Set
All five core container properties — direction, justify, align, wrap, gap — each labeled with what its value does to the main or cross axis.
Live Visual Preview
Drag, click, change — the preview updates instantly. Adjustable item count from 1 to 12 lets you see how settings behave with realistic content.
CSS + Tailwind v4 Output
Get vanilla CSS for stylesheets and a Tailwind v4 utility class string (using named utilities like justify-between, items-center where they exist).
100% Client-Side
No accounts, no uploads. Pure CSS-rendering preview — the browser does the layout exactly as your production code will.
CSS Flexbox Generator: Visual Layout With Copy-Paste CSS
A flexbox generator turns the five flex-container properties into clickable controls and shows a live CSS preview as you change them. Set flex-direction, justify-content, align-items, flex-wrap, and gap, adjust the item count from 1 to 12, then copy the vanilla CSS or Tailwind v4 utilities. It runs 100% in your browser, free, with no upload.
How to use the flexbox generator
- Pick a flex-direction —
rowfor a horizontal layout,columnfor a vertical stack. This sets which axis is the main axis. - Choose a justify-content value to position items along the main axis, and an align-items value to position them on the cross axis.
- Toggle flex-wrap to
wrapif items should flow onto new lines instead of overflowing one line. - Drag the gap slider for consistent spacing, and set the item count (1–12) to test how the layout behaves with realistic content.
- Load a preset (Centered, Space Between Nav, Card Grid, Vertical Stack) as a starting point, then copy the CSS or Tailwind v4 output.
What is flexbox and how does the main vs cross axis work?
Flexbox is the CSS Flexible Box Layout module for one-dimensional layout — arranging items in a single row or a single column and distributing the leftover space between them. The model has two axes. flex-direction sets the main axis (the direction items flow); the cross axis runs perpendicular to it. justify-content always works on the main axis, align-items always works on the cross axis — so switching from row to column swaps which property controls horizontal vs vertical.
Per the W3C CSS Flexible Box Layout Module Level 1 spec, each item has three flex factors. The flex shorthand resolves them: the initial value flex: initial is 0 1 auto (size to content, may shrink, never grows), while the single-value flex: 1 expands to 1 1 0 — a zero basis that makes every item share space equally regardless of content width. That difference is why flex: 1 gives true equal-width columns and flex: auto (1 1 auto) does not.
Worked examples: settings → CSS
Center a child both ways
display: flex; justify-content: center; align-items: center;
Logo-left, menu-right nav bar
display: flex; justify-content: space-between; align-items: center;
Responsive card grid (wraps to new rows)
display: flex; flex-wrap: wrap; gap: 16px; /* items: flex: 1 1 200px */
Edge case · flex: 1 vs flex: auto
Both let items grow, but only flex: 1 (1 1 0) produces equal-width columns — it ignores content width. flex: auto (1 1 auto) keeps each item's content size as the baseline, so a column with more text ends up wider. Use flex: 1 when you want every column the same width.
Flexbox Property Reference
| Property | Values | Purpose |
|---|---|---|
| flex-direction | row · row-reverse · column · column-reverse | Defines the primary axis. Row = horizontal flow (default in LTR). Column = vertical. |
| justify-content | flex-start · center · flex-end · space-between · space-around · space-evenly | Distributes items along the main axis. space-between is the classic nav-bar pattern. |
| align-items | flex-start · center · flex-end · stretch · baseline | Aligns items along the cross axis. Stretch (default) makes items fill the cross-axis dimension. |
| flex-wrap | nowrap · wrap · wrap-reverse | Whether items overflow on one line (nowrap) or wrap to new lines (wrap). |
| gap | 0 to any positive length | Spacing between items. Modern replacement for margin hacks; works in both row and column. |
| align-content | flex-start · center · flex-end · space-between · space-around · stretch | Aligns wrapped LINES (not items). Only has effect when flex-wrap allows wrapping. |
Flexbox vs CSS Grid — Which to Use When
| Aspect | Flexbox | CSS Grid |
|---|---|---|
| Layout dimension | One-dimensional (row OR column) | Two-dimensional (rows AND columns simultaneously) |
| Direction | Content-driven; items size to content | Container-driven; you define tracks explicitly |
| Best for | Navigation bars, button rows, card lists, modal layouts | Page-level layout, image galleries, dashboard panels |
| Item sizing | Distributes available space with grow/shrink | Tracks set explicitly with fr / minmax / repeat |
| Browser support | 99%+ global (Chrome 29+, Safari 9+, FF 28+, Edge 12+) | 98%+ global (Chrome 57+, Safari 10.1+, FF 52+) |
Rule of thumb: page-level layout = grid. Component-level layout inside a card = flexbox. Most production codebases use both heavily; neither replaces the other.
Six Flexbox Patterns You Will Use Constantly
Horizontally + vertically centered child
justify-content: center; align-items: center
Space-between navigation bar
justify-content: space-between
Equal-width grid (wraps to new rows)
flex-wrap: wrap; flex: 1 1 200px
Vertical stack with consistent spacing
flex-direction: column; gap: 16px
Push last item to far right
margin-left: auto on the last item
Sticky footer in column layout
flex-direction: column; main { flex: 1 }
The flexbox bug nobody warns you about: min-width: auto
Every flex item defaults to min-width: auto (and min-height: auto in a column). The CSS Flexbox spec says an item will not shrink below its content's min-content size — so one long word, a wide image, or a <pre> block refuses to compress and blows your layout past the container. This is the single cause behind almost every "text-overflow: ellipsis won't truncate inside flexbox" report.
The fix is one line: set min-width: 0 on the flex item (or give it any overflow value other than visible, such as overflow: hidden, which the spec resets min-width to 0 for). In nested flex layouts you often need min-width: 0 on every item in the chain leading to the text. The generator outputs container properties; remember this item-level rule when your real content overflows.
Runs 100% in your browser
Your settings never leave your device. The preview is rendered by your own browser's CSS engine — not a canvas approximation — so the layout you see is exactly what your production code produces. The CSS and Tailwind v4 strings are built locally in JavaScript and copied with your browser clipboard: no uploads, nothing leaves your device. I tested every preset, each flex-direction, both wrap modes, and item counts from 1 to the cap of 12; the Tailwind output falls back to arbitrary values like gap-[14px] only when a gap does not map to a named step.
Frequently asked questions
Is this CSS flexbox generator free?
Yes — 100% free with no signup and no usage cap. The CSS and Tailwind v4 output it produces is yours to paste into any personal or commercial project.
Does it run in my browser or upload my data?
Everything runs in your browser. The preview uses your browser's real CSS engine and the output is built in JavaScript locally, so nothing is uploaded and the tool works offline once loaded.
When should I use flexbox instead of CSS grid?
Use flexbox for one-dimensional layout — a row of buttons, a nav bar, a column of cards. Use the CSS Grid Generator for two-dimensional layout with explicit rows and columns. Most pages use both: grid for the shell, flexbox inside the cells.
Why won't my flex item shrink below its text?
Flex items default to min-width: auto, which blocks shrinking below the content's min-content size. Set min-width: 0 (or overflow: hidden) on the item to let it compress — this is the fix for ellipsis truncation failing inside flexbox.
Is the Tailwind output v3 or v4?
Tailwind v4. It uses named utilities where they map directly (justify-between, items-center, flex-row) and arbitrary values such as gap-[14px] when a gap does not match a named step. The named utilities are identical in v3.
Related CSS Utilities
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CSS BeautifierFormat the CSS you copy out
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Last updated: June 2, 2026 · Runs 100% in your browser — no uploads, nothing leaves your device.
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