# How to Generate CSS Flexbox Layouts

> Build flexible CSS layouts visually by configuring flex container and item properties, then copy the generated CSS code.

- URL: https://www.browserutils.dev/how-to/generate-css-flexbox
- Published: 2026-09-27
- Updated: 2026-07-02

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## Step 1: Set container properties

Configure the flex container by choosing flex-direction, justify-content, align-items, flex-wrap, and gap values using visual controls.

## Step 2: Configure flex items

Add items and set their individual flex-grow, flex-shrink, flex-basis, and align-self properties to control how they behave within the container.

## Step 3: Preview the layout

See a live preview of your flexbox layout as you adjust properties. Resize the preview area to test how items respond at different widths.

## Step 4: Copy the CSS code

Copy the generated CSS for both the container and items. Paste it into your stylesheet and apply the class names to your HTML elements.

Flexbox is the foundation of modern CSS layouts, but remembering which combination of `justify-content`, `align-items`, and `flex-wrap` produces the layout you want can be frustrating. The [CSS Flexbox Generator](/tools/css-flexbox-generator) lets you configure layouts visually and generates the exact CSS you need, eliminating the trial-and-error cycle.

## Understanding flexbox layout

Flexbox works along two axes: the main axis (defined by `flex-direction`) and the cross axis (perpendicular to it). All flexbox behavior stems from how items are distributed along these two axes.

The container properties control the overall layout: `flex-direction` sets the main axis (row or column), `justify-content` distributes items along the main axis, `align-items` aligns items along the cross axis, `flex-wrap` controls whether items wrap to new lines, and `gap` sets spacing between items.

Item properties control individual behavior within the container: `flex-grow` determines how extra space is distributed (a value of `1` means the item grows to fill available space), `flex-shrink` controls how items shrink when space is tight, and `flex-basis` sets the initial size before growing or shrinking is applied.

The shorthand `flex: 1 1 0%` (grow, shrink, basis) is the most common pattern for equal-width items. For a fixed-width item that does not flex, use `flex: 0 0 auto` with an explicit width.

## Tips and best practices

- **Use `gap` instead of margins.** The `gap` property on the flex container is cleaner than adding margins to items. It only adds space between items, not around the outside edges.
- **Start with `flex-wrap: wrap` for responsive layouts.** Without wrapping, flex items will shrink indefinitely to fit on one line, often squishing content. Wrapping lets items flow to new lines when space runs out.
- **Use `min-width: 0` on flex items to prevent overflow.** By default, flex items will not shrink below their content size. If long text or large images overflow, adding `min-width: 0` allows the item to shrink properly.
- **Combine `flex-grow` with `flex-basis` for proportional layouts.** Instead of using percentages, set `flex-basis: 0` and use different `flex-grow` values to create proportional columns (e.g., `flex: 2` and `flex: 1` for a 2:1 ratio).

## Common issues

- **Items not centering vertically.** Make sure the flex container has an explicit height. If the container's height matches its content height, there is no extra space for `align-items: center` to work with.
- **Last row of wrapped items stretching unexpectedly.** When using `justify-content: space-between` with wrapping, the last row may spread items across the full width if it has fewer items. Use `gap` with `flex-basis` percentages instead for grid-like wrapped layouts.
- **Flex items ignoring width.** When `flex-basis` is set, it overrides `width` in the main axis direction. Use `flex-basis` instead of `width` for sizing flex items, or set `flex-basis: auto` to respect the `width` property.