CSS Grid vs Flexbox: Which one to use and when?

One of the most common questions in frontend development is: Should I use Grid or Flexbox?. The short answer is: both. They are not rivals; they are teammates.

The Fundamental Difference

• Flexbox is one-dimensional. It works best for distributing items in a single line (row) OR a single column.
• CSS Grid is two-dimensional. It works for controlling rows AND columns simultaneously.

Flexbox: King of Components

Use Flexbox when you want to align items within a container, like a navigation bar or a product card.

.navbar {
  display: flex;
  justify-content: space-between; /* Spacing */
  align-items: center; /* Vertical centering */
}

When to choose Flexbox:

• Aligning small groups of items.
• Distributing space within a component.
• If you only care about one direction (horizontal or vertical).

CSS Grid: King of Layout

Use Grid when defining the overall structure of your page or a complex gallery.

.layout {
  display: grid;
  grid-template-columns: 200px 1fr; /* Fixed sidebar, flexible content */
  grid-template-rows: auto 1fr auto; /* Header, Body, Footer */
  gap: 20px;
}

When to choose Grid:

• Creating the main layout structure (Header, Sidebar, Main, Footer).
• 2D image galleries.
• When you need to overlap items (z-index in cells).

The Power of Combining Them

The most common pattern in 2024 is using Grid for the skeleton of the page and Flexbox for the cells (the individual components).

/* Main Layout */
body { display: grid; ... }

/* Card Component inside the Grid */
.card { display: flex; flex-direction: column; }

Mastering both is essential for any modern frontend developer. Stop using float and tables and embrace the future!