CSS Flexbox Generator: Visual Tool for Flexible Layouts

How to Use Our CSS Flexbox Generator

Our generator is split into two main control panels: Container Properties (the parent element) and Item Properties (the child elements within the container). Adjust the settings in each panel to see the layout change in real-time.

Parent Container Settings

These options control the overall layout and behavior of the flex container itself.

• Display: This is the magic switch that enables Flexbox. It’s set to flex by default.

• Flex Direction: This defines the main axis of your container, determining the direction your items are placed.

  • row: Items are arranged horizontally, from left to right (default).

  • row-reverse: Items are arranged horizontally, but from right to left.

  • column: Items are stacked vertically, from top to bottom.

  • column-reverse: Items are stacked vertically, but from bottom to top.

• Flex Wrap: This controls whether your items should wrap onto a new line if they run out of space in the container.

  • nowrap: All items will be forced onto one line, which may cause them to overflow the container (default).

  • wrap: Items will wrap onto a new line from top to bottom if needed.

  • wrap-reverse: Items will wrap onto a new line from bottom to top if needed.

• Justify Content: This property aligns items along the main axis (horizontally if flex-direction is row, vertically if it’s column). It manages the distribution of extra space.

  • flex-start: Packs items toward the start of the main axis.

  • flex-end: Packs items toward the end of the main axis.

  • center: Packs items in the center of the main axis.

  • space-between: Distributes items evenly; the first item is at the start, the last is at the end.

  • space-around: Distributes items evenly with equal space around each item.

  • space-evenly: Distributes items so the spacing between any two items and the space to the edges is equal.

• Align Items: This aligns items along the cross axis (vertically if flex-direction is row, horizontally if it’s column). Think of it as vertical alignment for a single row of items.

   

  • stretch: Stretches items to fill the container (default).

     

  • flex-start: Aligns items to the start of the cross axis.

     

  • flex-end: Aligns items to the end of the cross axis.

     

  • center: Centers items along the cross axis.

  • baseline: Aligns items based on their text baseline.

• Align Content: This property only applies when there are multiple lines of flex items (i.e., when flex-wrap is set to wrap). It aligns the entire block of content (all the lines) within the container.

• Gap: A shorthand for row-gap and column-gap, this property sets the size of the gutters between flex items without affecting the space around the outer edges of the container.

Child Item Settings

These settings allow you to control individual flex items. You can select an item in the visual preview to apply specific properties to it.

• Flex Grow: A number that dictates how much an item will grow relative to the others if there’s extra space in the container. A value of 0 means the item won’t grow. A value of 1 on all items means they will share the extra space equally.

• Flex Shrink: A number that dictates how much an item will shrink relative to the others if there isn’t enough space. A value of 1 means it will shrink, while 0 prevents it from shrinking.

• Flex Basis: This defines the default size of an item before the remaining space is distributed. It can be a length (e.g., 150px) or auto.

• Align Self: This allows you to override the default align-items property for a single flex item.

Understanding Your Results

After adjusting the settings to achieve your desired layout, the generator provides you with a clean, ready-to-use CSS code snippet. This is what the output means and how to use it.

The result box will contain two CSS rules:

1. The Container Rule: This rule targets your parent element. It will have a selector like .flex-container and will contain all the properties you set in the “Parent Container Settings” panel.

   CSS

    

   .flex-container {
     display: flex;
     flex-direction: row;
     justify-content: space-between;
     align-items: center;
     gap: 10px;
   }
   

2. The Item Rule(s): These rules target the child elements. You might have a general .flex-item rule, as well as specific rules for items you modified individually (e.g., .item-3).

   CSS

    

   .flex-item {
     flex-grow: 1;
     flex-basis: 100px;
   }
   
   .item-3 {
     align-self: flex-end; /* This item has a specific override */
   }
   

How to Implement the Code:

1. HTML Structure: Make sure your HTML follows the parent/child structure.

   HTML

    

   <div class="flex-container">
     <div class="flex-item item-1">1</div>
     <div class="flex-item item-2">2</div>
     <div class="flex-item item-3">3</div>
   </div>
   

2. Copy & Paste CSS: Copy the generated CSS from the result box and paste it into your website’s stylesheet (e.g., style.css).

3. Adjust Selectors: Change the class names (.flex-container, .flex-item) to match the class names you are using in your own HTML.

Frequently Asked Questions

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

This is the most common point of confusion for Flexbox beginners. The key is to think in terms of axes:

• justify-content works on the Main Axis. If your flex-direction is row (the default), it controls horizontal alignment. If flex-direction is column, it controls vertical alignment.

• align-items works on the Cross Axis. If your flex-direction is row, it controls vertical alignment. If flex-direction is column, it controls horizontal alignment.

Here’s a simple table to help you remember:

When should I use Flexbox instead of CSS Grid?

Both are powerful layout systems, but they are designed for different use cases.

• Use Flexbox for one-dimensional layouts—either a row or a column. It excels at distributing space along a single axis. Think of navigation bars, aligning items in a card, or a list of articles.

• Use CSS Grid for two-dimensional layouts—rows and columns simultaneously. It’s perfect for complex page layouts, like a photo gallery, a dashboard interface, or anything that needs precise alignment in both dimensions.

You can also use them together. It’s common to use Grid for the main page structure and Flexbox to align the content inside a grid item.

How do I make my Flexbox layout responsive?

Flexbox is inherently responsive. The key property for responsiveness is flex-wrap.

• Set flex-wrap: wrap; on the container. This allows items to wrap to the next line when the screen becomes too narrow.

• Use flex-grow, flex-shrink, and flex-basis on the items. A common pattern is flex: 1 1 250px;. This tells each item:

  • flex-grow: 1: Grow to fill any extra space.

  • flex-shrink: 1: Shrink if there isn’t enough space.

  • flex-basis: 250px: Try to be at least 250px wide.

When combined, these properties create a layout where items will try to be 250px wide. If there’s room for three on a large screen, they’ll grow to fill the space. On a smaller screen, they might wrap so only two or one appear per line.

What do flex-grow, flex-shrink, and flex-basis actually do?

These three properties, often used in the flex shorthand, control the flexibility of items. Let’s break it down with an example.

Imagine a container that is 600px wide. Inside, you have two items:

• Item A: flex: 1 1 200px; (grow: 1, shrink: 1, basis: 200px)

• Item B: flex: 2 1 200px; (grow: 2, shrink: 1, basis: 200px)

The total flex-basis is 200px + 200px = 400px. The container is 600px, so we have 600px - 400px = 200px of extra space.

This extra space is distributed based on the flex-grow ratio, which is 1:2.

• Total grow factor: 1 + 2 = 3.

• Item A gets (1 / 3) of the extra space: (1/3) * 200px = 66.67px.

• Item B gets (2 / 3) of the extra space: (2/3) * 200px = 133.33px.

Final sizes:

• Item A: 200px (basis) + 66.67px (growth) = 266.67px.

• Item B: 200px (basis) + 133.33px (growth) = 333.33px.

flex-shrink works similarly but applies when the container is too small and items need to shrink.

How do I center something both vertically and horizontally with Flexbox?

This is one of Flexbox’s most celebrated features. It’s incredibly simple. On the parent container, apply these three properties:

.parent-container {
  display: flex;
  justify-content: center; /* Centers horizontally */
  align-items: center;     /* Centers vertically */
  min-height: 100vh;         /* Make container fill the viewport height */
}

Any child element inside .parent-container will now be perfectly centered.

Why are my flex items overflowing their container?

This usually happens for one of two reasons:

1. flex-wrap is not set. By default, flex-wrap is nowrap. This forces all items onto a single line, even if it means they overflow the container’s boundaries. The fix is to set flex-wrap: wrap; on the container.

2. An item has a minimum width. If a flex item has a min-width that is larger than the available space, it will not shrink below that size and may overflow. Check your child elements for properties like min-width.

Can I create equal-height columns with Flexbox?

Yes, easily. This is a default behavior of Flexbox. As long as the align-items property on the container is set to its default value of stretch, all flex items in a row will automatically stretch to be as tall as the tallest item.

What is the gap property and is it better than using margin?

The gap property defines the space between items in a flex container. For example, gap: 16px; will put 16px of space between each item, both horizontally and vertically (if wrapped).

Using gap is often better than margin for a few reasons:

• Simplicity: You apply it once on the parent container instead of to every child item.

• No Edge Margin: gap only adds space between items. It doesn’t add unwanted space at the start of the first item or the end of the last item, which often happens with margins and requires complex selectors (:not(:last-child)) to fix.

• Consistency: It works the same way in both Flexbox and CSS Grid, making your spacing rules more consistent across different layout methods.

What’s the difference between align-content and align-items?

This is another common point of confusion.

• align-items aligns items within a single line. It controls the vertical position of items in a row.

• align-content only works when you have multiple lines of items (i.e., flex-wrap: wrap is active). It aligns the entire block of wrapped lines within the container’s available space. Think of it as justify-content for the cross axis.

If you only have one line of flex items, align-content has no effect.

What are some real-world examples of Flexbox layouts?

You see Flexbox everywhere on the modern web. Common use cases include:

• Navigation Bars: Aligning a logo on the left, navigation links in the center, and a search bar/button on the right.

• Card Layouts: Creating a responsive grid of cards (e.g., blog posts, products) that wrap neatly on smaller screens.

• Form Controls: Aligning a label and an input field side-by-side.

• Media Objects: Placing an image on the left and a block of text on the right that wraps properly.

• Button Groups: Distributing buttons evenly within a container.

Now that you’ve mastered your layout with our CSS Flexbox Generator, why not enhance the visual appeal of your elements? Give your buttons and backgrounds a modern look with our CSS Gradient Generator, or make your cards pop off the page with our intuitive CSS Box Shadow Generator.