CSS Flexbox Generator — Visual Flex Layout Builder with Live Preview
Build CSS flexbox layouts visually. Toggle direction, justify, align, wrap, gap with live preview. Copies clean, production-ready CSS.
About CSS Flexbox Generator
A CSS flexbox generator is a visual tool that lets you compose `display: flex` containers by toggling each flex property and seeing the result in real time. The ZTools CSS Flexbox Generator covers every flex container property (`flex-direction`, `justify-content`, `align-items`, `align-content`, `flex-wrap`, `gap`) and per-child properties (`flex-grow`, `flex-shrink`, `flex-basis`, `align-self`), generating both the parent and child CSS in copy-paste-ready form. Designed for developers who know flexbox conceptually but find the property combinations hard to memorize.
Use cases
- Building a navbar with logo on left, links centered, CTA on right. Set `justify-content: space-between` plus a flex spacer trick, see the result, copy the CSS. Faster than tweaking margin values until it looks right.
- Centering content vertically AND horizontally. The classic "how do I center a div" — set `justify-content: center` + `align-items: center` on the parent. The generator shows you exactly that combination with a live preview.
- Building responsive card grids that wrap gracefully. Set `flex-wrap: wrap` + `gap: 1rem`, watch cards reflow as the preview width changes. Copy the CSS and apply to your real grid.
- Learning flexbox without trial-and-error. Each property has a tooltip explaining its behavior. Toggle and see — the preview makes flexbox's otherwise-confusing rules immediately visible.
How it works
- Choose the number of children. Slider from 1 to 12 children. Each child renders as a colored block in the preview.
- Set parent (container) properties. Toggle `flex-direction`, `flex-wrap`, `justify-content`, `align-items`, `align-content`, `gap`. Each click updates the preview instantly.
- Optionally set per-child properties. Click any child block to set its `flex-grow`, `flex-shrink`, `flex-basis`, or `align-self` independently.
- Preview at multiple widths. Drag the preview width slider to test how the layout reflows on narrow vs wide screens.
- Copy generated CSS. Output includes a `.container { display: flex; ... }` block plus per-child overrides if you set any. One click copies the full snippet.
Examples
Input: flex-direction: row, justify-content: space-between, align-items: center
Output: .container {
display: flex;
flex-direction: row;
justify-content: space-between;
align-items: center;
}
Classic navbar layout pattern.
Input: flex-direction: column, gap: 1rem, align-items: stretch
Output: .container {
display: flex;
flex-direction: column;
gap: 1rem;
align-items: stretch;
}
Vertical card stack with consistent spacing.
Frequently asked questions
When should I use flexbox vs grid?
Flexbox for one-dimensional layouts (a row OR a column). Grid for two-dimensional layouts (rows AND columns simultaneously). Both can be combined in the same page.
Why doesn't `justify-content: center` center my content vertically?
Because `justify-content` works on the main axis (horizontal in a row layout). For vertical centering in a row, use `align-items: center`. The generator labels each property by axis to avoid this confusion.
What does `flex: 1` mean?
Shorthand for `flex: 1 1 0%` — grow to fill available space, shrink if needed, and start from 0 width. Common for equal-width children: `<div style="flex: 1">` × N gives N equal columns.
How do I make children wrap to a new line?
Set `flex-wrap: wrap` on the container. Without it, children shrink to fit on one line (or overflow). The generator includes wrap toggling so you can see the effect immediately.
What's the difference between `gap` and `margin`?
`gap` applies space between children only — no leading/trailing space at the container edges. `margin` on children produces both interior and edge space, often requiring `:last-child` overrides. Prefer `gap` in modern CSS.
Is the generated CSS production-ready?
Yes — uses standard, evergreen-browser-supported properties. No vendor prefixes needed since 2018.
Pro tips
- Default to `gap` for spacing between flex children — no more `:not(:last-child) { margin-right }` hacks.
- For equal-width columns, use `flex: 1` on every child instead of fixed widths.
- Combine flexbox with `min-width: 0` on children when text might overflow — fixes the "ellipsis not working" gotcha.
- Use the generator to learn flexbox visually, then graduate to writing CSS by hand.
Reviewed by Ahsan Mahmood · Last updated 2026-05-05 · Part of ZTools.
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