Ever fight with a row of boxes that will not line up the way you want? Flexbox solves that, and the CSS Flexbox Generator writes the container code for you. You pick the settings, and it builds a ready to paste rule block.
This tool is for web developers, designers, and students learning layout. You change six controls, watch a live preview react, and copy the finished CSS. No flex syntax needs to be memorized first.
Table of Contents
- What the Tool Does
- How to Use It, Step by Step
- How the Generated CSS Is Built
- Worked Example
- How to Read the Results
- What Each Flex Property Changes
- Limitations and Assumptions
- FAQs About the CSS Flexbox Generator
What the Tool Does
The generator builds one CSS rule for a flex container. It does not style the child items beyond placing them in the preview. Six controls drive the output and the live stage.
- flex-direction: choose row, row-reverse, column, or column-reverse.
- justify-content: flex-start, center, flex-end, space-between, space-around, or space-evenly.
- align-items: stretch, center, flex-start, flex-end, or baseline.
- flex-wrap: nowrap, wrap, or wrap-reverse.
- gap: a slider from 0 to 50 pixels.
- Preview Items (preview only): 3, 4, or 5 preview boxes.
Five cards at the top show your current direction, justify, align, wrap, and gap values. The Copy CSS button copies the generated rule to your clipboard.
How to Use It, Step by Step
- Pick a flex-direction. The default is row, which lays items left to right.
- Pick a justify-content value to space items along the main axis.
- Pick an align-items value to position items on the cross axis.
- Pick a flex-wrap value. Wrap lets items drop to a new line.
- Drag the gap slider to set the space between items in pixels.
- Pick the Preview Items count to add preview boxes.
- Press Copy CSS and paste the rule into your stylesheet.
How the Generated CSS Is Built
There is no math here. The tool joins your six choices into a fixed template. It always starts with display: flex and then lists each property you set.
flex-direction+justify-content+align-items+flex-wrap + gap=display: flex Rule
The gap value is read as a number and the tool appends px to it. The six lines appear in the output box in the same order every time.
Worked Example
Priya opens the tool and leaves every control at its starting value. That means row, center, center, wrap, a 16 pixel gap, and 3 items. The output box shows this exact rule.
| Property | Selected Value | Line In Output |
|---|
| display | fixed | display: flex; |
| flex-direction | row | flex-direction: row; |
| justify-content | center | justify-content: center; |
| align-items | center | align-items: center; |
| flex-wrap | wrap | flex-wrap: wrap; |
| gap | 16 | gap: 16px; |
Next Priya sets direction to column, justify to space-between, align to flex-start, wrap to nowrap, and the gap to 24. The output then reads gap: 24px and the three boxes stack in a single column.
How to Read the Results
Direction, Justify Content, Align Items, Flex Wrap, and Gap are the five cards at the top. They echo five of your settings so you can confirm them at a glance.
The live stage is the dashed box. It applies your settings to real boxes so you see the layout before you copy anything.
The Generated Container CSS box holds the final rule. Apply it to the parent element that wraps your items, not to the items themselves.
What Each Flex Property Changes
Flexbox has a main axis and a cross axis. With row, the main axis runs across and the cross axis runs down. With column, those two axes swap.
justify-content moves items along the main axis. align-items moves them along the cross axis. Space-between pushes the first and last item to the edges.
The gap sets even spacing between items without side margins. For two dimensional grids with rows and columns, the CSS Grid layout generator is a better fit. To move or rotate an element, try the transform code builder.
Flexbox pairs well with other visual styles. You can add depth with the box shadow builder and shrink your finished stylesheet using the CSS minifier. More utilities sit in the developer tools hub.
Limitations and Assumptions
- The tool styles the container only. It does not output flex-grow, flex-shrink, flex-basis, or order for the items.
- The tool does not write media queries. Responsive breakpoints for each screen size are up to you.
- The gap value shows live next to the slider and in a Gap card. It accepts whole pixels from 0 to 50.
- Only pixel gaps are offered. Percent, rem, and separate row or column gaps are not available.
- Every option is a valid CSS keyword, so the rule should work in all modern browsers that support Flexbox.
- The copy button tries the clipboard first, then a fallback. If both fail, it shows a message so you can copy by hand.
FAQs About the CSS Flexbox Generator
Does the Tool Generate Code for the Child Items?
No. It writes the container rule only, such as display, direction, justify, align, wrap, and gap. Properties like flex-grow and order are not produced.
Where Do I Paste the Generated CSS?
Paste it on the parent element that holds your items. That parent becomes the flex container, and its direct children become flex items.
Why Do the Preview Items Not Appear in the CSS?
Preview Items only adds boxes to the preview. It helps you see how items wrap and align. The count is never part of the exported rule.
What Is the Difference Between justify-content and align-items?
Justify-content spaces items along the main axis. Align-items positions them on the cross axis. The axes swap when you switch between row and column.
Should I Use Flexbox or CSS Grid?
Flexbox is strong for a single row or column of items. CSS Grid is better when you need both rows and columns at once.
Does the Copy Button Store My Settings Anywhere?
No. The rule is built in your browser and copied to your clipboard. Nothing is saved or sent to a server.
This calculator gives general estimates only and is not professional advice. Reviewed for general accuracy by Prof. Dr. Khalil Mudassar, PhD.