CSS Flexbox Generator

CSS Flexbox Generator Online — Visual Builder with Tailwind Output

Build CSS Flexbox layouts visually and copy the code in seconds. Adjust every container and item property — flex-direction, justify-content, align-items, gap, flex-grow — and watch the live preview update instantly. No configuration, no signup, no install.

Unlike other generators, this tool outputs Tailwind classes and vanilla CSS simultaneously. Switch between Tailwind, CSS, and React/JSX tabs and copy whichever format matches your stack. Ten preset layouts (Navbar, Centered Hero, Card Grid, Sidebar, Holy Grail, and more) let you start from a real-world pattern rather than scratch.

How to Use the CSS Flexbox Generator

Building a flexbox layout takes under a minute:

1. Choose a preset — click any preset in the gallery at the top (Navbar, Card Grid, Sidebar…) to load a complete real-world configuration. The live preview and code update immediately.
2. Adjust container properties — use the controls on the left to change flex-direction, flex-wrap, justify-content, align-items, align-content, and gap. The preview reflects every change in real time.
3. Fine-tune individual items — click any colored box in the preview (or the item tabs below) to edit that item's flex-grow, flex-shrink, flex-basis, align-self, and order.
4. Copy your code — switch between Tailwind, CSS, or React tabs in the code panel, then hit Copy or press Shift+Enter. Use Download to save the CSS file.

If a property has no effect in your current configuration — for example, align-content when flex-wrap is set to nowrap — a contextual warning explains exactly why and how to fix it.

CSS Flexbox Examples

These are real outputs from the generator for common layout patterns:

Navbar (space-between, center)

.container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
}

Tailwind: flex justify-between items-center gap-4

Centered hero (both axes)

.container {
  display: flex;
  justify-content: center;
  align-items: center;
}

Tailwind: flex justify-center items-center

Card grid with wrapping

.container {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

Tailwind: flex flex-wrap gap-4

React/JSX output for column stack

const containerStyle = {
  display: 'flex',
  flexDirection: 'column',
  gap: '8px',
};
// <div style={containerStyle}>…</div>

What Is CSS Flexbox?

CSS Flexible Box Layout (Flexbox) is a one-dimensional layout model — it arranges items in a single row or column. Unlike older layout methods, Flexbox gives you precise control over how items grow, shrink, and align even when their sizes are unknown or dynamic.

Flexbox operates on two axes: the main axis (set by flex-direction) and the cross axis (perpendicular to the main). justify-content controls alignment on the main axis; align-items controls it on the cross axis. This distinction is where most developers get confused, and why contextual warnings are so valuable in practice.

Common Use Cases

• Navigation bars: flex, justify-content: space-between, align-items: center — the classic pattern for a logo on the left and links on the right.
• Centering content: display: flex; justify-content: center; align-items: center on a parent with a defined height. The fastest way to center a div.
• Card rows: flex, flex-wrap: wrap, gap — cards line up in a row and wrap to the next line when the viewport is too narrow.
• Sidebar + content: flex, flex-wrap: nowrap, align-items: stretch — one narrow item (flex-shrink: 0, flex-basis: 260px) and one that grows to fill remaining space (flex-grow: 1).
• Form inputs: flex, align-items: center, gap — label and input on the same line with consistent vertical alignment.
• Button groups and pill rows: flex, flex-wrap: wrap, justify-content: flex-end, gap — buttons wrap to next line on small screens without breaking the layout.

Flexbox vs. CSS Grid: When to Use Each

The simple rule: Flexbox for 1D (one direction at a time), Grid for 2D (rows and columns simultaneously). Most modern pages use Grid for the macro layout and Flexbox inside each component.

Frequently Asked Questions

What is the difference between justify-content and align-items in Flexbox?

justify-content controls alignment on the main axis — horizontal when flex-direction is row, vertical when it is column. align-items controls alignment on the cross axis — the perpendicular direction. To center an element both horizontally and vertically in a container, set display: flex; justify-content: center; align-items: center on the parent and give the parent a defined height.

Why is align-content not working in my Flexbox layout?

align-content only works when two conditions are met: (1) flex-wrap is set to wrap or wrap-reverse, and (2) items have actually wrapped to multiple lines. On a single-line container — the default flex-wrap: nowrap — align-content has no visual effect at all. Use align-items instead for single-line containers. The generator shows a warning when you set align-content with nowrap active.

What does flex: 1 mean in CSS?

flex: 1 is shorthand for flex: 1 1 0%, meaning the item can grow (flex-grow: 1), can shrink (flex-shrink: 1), and starts from a base size of zero (flex-basis: 0%). When multiple items all have flex: 1, they share available space equally regardless of their content size — the most common pattern for equal-width columns.

How do I center a div vertically and horizontally with Flexbox?

Apply to the parent container: display: flex; justify-content: center; align-items: center. The parent must have a defined height — either a fixed value, height: 100vh, or it must inherit height from its own parent. Without a height, vertical centering has no space to work with.

Does the generator export Tailwind CSS classes?

Yes — and it shows Tailwind and vanilla CSS at the same time. Switch between the Tailwind, CSS, and React tabs in the code panel. Tailwind output uses standard utility classes (flex, justify-between, items-center, gap-4, etc.). For gap values not on the default Tailwind scale, the generator outputs the arbitrary value syntax: gap-[20px].

What is the difference between align-items and align-content in Flexbox?

align-items applies to all items within a single line — it controls how they align on the cross axis within their row. align-content applies to the lines themselves when there are multiple wrapped lines (requires flex-wrap: wrap). Think of it this way: align-items is per-item, align-content is per-row.

Resources

• MDN — CSS Flexible Box Layout — the complete specification reference with browser compatibility data.
• CSS-Tricks — A Complete Guide to Flexbox — the most widely referenced visual guide to every Flexbox property.