CSS Flexbox is the most widely used layout system in modern web development. A flexbox generator lets you build layouts visually — adjusting direction, alignment, wrapping, and gaps — and copy the generated CSS instantly.
Build Flexbox Layouts Visually
Adjust properties, see live preview, copy CSS. No manual coding needed.
Flexbox Basics: Container vs Items
Flexbox has two levels: the flex container (parent) and flex items (children).
.container { display: flex; }| Property | Applies To | Values | Default |
|---|---|---|---|
| flex-direction | Container | row, column, row-reverse, column-reverse | row |
| justify-content | Container | flex-start, center, flex-end, space-between, space-around, space-evenly | flex-start |
| align-items | Container | flex-start, center, flex-end, stretch, baseline | stretch |
| flex-wrap | Container | nowrap, wrap, wrap-reverse | nowrap |
| gap | Container | Any length (px, rem) | 0 |
| flex-grow | Item | Number (0, 1, 2...) | 0 |
| flex-shrink | Item | Number | 1 |
| flex-basis | Item | Length or auto | auto |
Common Flexbox Layout Patterns
Center Everything
.container {
display: flex;
justify-content: center;
align-items: center;
min-height: 100vh;
}Navigation Bar
.nav { display: flex; justify-content: space-between; align-items: center; }Card Grid (Wrapping)
.grid {
display: flex;
flex-wrap: wrap;
gap: 1rem;
}
.card { flex: 1 1 300px; }Sidebar + Content
.layout { display: flex; }
.sidebar { flex: 0 0 250px; }
.content { flex: 1; }Footer Stick to Bottom
.page { display: flex; flex-direction: column; min-height: 100vh; }
.content { flex: 1; }
.footer { flex-shrink: 0; }justify-content vs align-items: The Key Difference
| Property | Axis | When direction=row | When direction=column |
|---|---|---|---|
| justify-content | Main axis | Horizontal | Vertical |
| align-items | Cross axis | Vertical | Horizontal |
justify-content = distribute along the FLOW direction. align-items = position ACROSS the flow. In row layout: justify = horizontal, align = vertical. In column layout: they swap.
The flex Shorthand Explained
flex: grow shrink basis;
flex: 1; /* = flex: 1 1 0% */
flex: auto; /* = flex: 1 1 auto */
flex: none; /* = flex: 0 0 auto */
flex: 0 0 200px; /* Fixed 200px, no grow/shrink */flex: 1 is the most useful value — it makes an item grow to fill available space. Use flex: 1 1 0% for equal-width items regardless of content.
Flexbox vs CSS Grid: When to Use Which
| Scenario | Use Flexbox | Use Grid |
|---|---|---|
| Navigation bars | Yes | No |
| Centering content | Yes | Yes |
| Card layouts (variable sizes) | Yes | Yes |
| Magazine/dashboard layouts | No | Yes |
| Form alignment | Yes | Yes |
| Two-dimensional grid | No | Yes |
| One-dimensional flow | Yes | No |
Flexbox = one direction (row OR column). Grid = two directions (rows AND columns). In practice, most components use Flexbox; page layouts use Grid.
Responsive Flexbox Patterns
/* Cards: 3 per row on desktop, stack on mobile */
.cards { display: flex; flex-wrap: wrap; gap: 1rem; }
.card { flex: 1 1 300px; /* Grow, shrink, min 300px */ }
/* Stack on mobile, row on desktop */
.nav {
display: flex;
flex-direction: column;
}
@media (min-width: 768px) {
.nav { flex-direction: row; }
}How to Use the Tool (Step by Step)
- 1
Open the Generator
Navigate to CSS Flexbox Generator on ToolsArena.
- 2
Set Container Properties
Choose flex-direction, justify-content, align-items, wrap, and gap.
- 3
Add and Configure Items
Add flex items, set flex-grow, flex-shrink, and flex-basis.
- 4
Preview Live
See your layout update in real-time as you adjust.
- 5
Copy CSS
Copy the generated CSS for container and items.
Frequently Asked Questions
What is CSS Flexbox?+−
Flexbox is a CSS layout model for distributing space and aligning items in a container along a single axis (row or column). It handles responsive sizing, centering, spacing, and ordering without floats or positioning hacks.
What is the difference between justify-content and align-items?+−
justify-content aligns items along the main axis (horizontal for row, vertical for column). align-items aligns along the cross axis. Think: justify = along the flow, align = across the flow.
When should I use Flexbox vs Grid?+−
Flexbox for one-dimensional layouts (navbars, card rows, button groups). Grid for two-dimensional layouts (page layouts, dashboards, magazine grids). Most components use Flexbox; page structure uses Grid.
What does flex: 1 mean?+−
flex: 1 is shorthand for flex-grow: 1, flex-shrink: 1, flex-basis: 0%. It makes the item grow to fill all available space. Multiple items with flex: 1 share space equally.
How do I center a div with Flexbox?+−
On the parent: display: flex; justify-content: center; align-items: center; — this centers the child both horizontally and vertically. Add min-height: 100vh for full-page centering.
What is the gap property?+−
gap sets spacing between flex items without margins. gap: 1rem adds 16px between all items. It replaced the old margin-based spacing hack and works in all modern browsers.
Is this tool free?+−
Yes. Generate unlimited Flexbox layouts in your browser. Copy CSS instantly.
Build Flexbox Layouts Visually
Adjust properties, see live preview, copy CSS. No manual coding needed.
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