CSS Grid vs Flexbox - When to Use Each Layout Method

Obaydur Rahman

Feb 3, 20258 min read

CSS Grid and Flexbox are two powerful layout systems that have revolutionized how we build web interfaces. While they can sometimes achieve similar results, each has distinct strengths that make them ideal for different scenarios.

Understanding the Fundamentals

Flexbox: One-Dimensional Layout

Flexbox excels at arranging items in a single dimension - either horizontally or vertically.

.flex-container {
    display: flex;
    flex-direction: row; /* or column */
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
}

.flex-item {
    flex: 1; /* Grow to fill available space */
    min-width: 200px;
}

CSS Grid: Two-Dimensional Layout

CSS Grid handles both rows and columns simultaneously, perfect for complex layouts.

.grid-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    grid-template-rows: auto 1fr auto;
    gap: 2rem;
    min-height: 100vh;
}

.grid-item {
    grid-column: span 2; /* Span across 2 columns */
}

When to Use Flexbox

Perfect for horizontal navigation with flexible spacing:

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
}

.nav-links {
    display: flex;
    gap: 2rem;
    list-style: none;
}

.nav-item {
    white-space: nowrap;
}

<nav class="navbar">
    <div class="logo">Brand</div>
    <ul class="nav-links">
        <li class="nav-item"><a href="/">Home</a></li>
        <li class="nav-item"><a href="/about">About</a></li>
        <li class="nav-item"><a href="/contact">Contact</a></li>
    </ul>
    <button class="menu-toggle">Menu</button>
</nav>

2. Card Layouts

Flexible cards that adapt to content:

.card-container {
    display: flex;
    flex-wrap: wrap;
    gap: 1.5rem;
    justify-content: center;
}

.card {
    flex: 1 1 300px; /* Grow, shrink, basis */
    max-width: 400px;
    display: flex;
    flex-direction: column;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.card-content {
    flex: 1; /* Take up remaining space */
    padding: 1.5rem;
}

.card-actions {
    padding: 1rem 1.5rem;
    border-top: 1px solid #eee;
}

3. Form Controls

Aligning form elements with consistent spacing:

.form-group {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1rem;
}

.form-row {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.form-field {
    flex: 1;
    min-width: 200px;
}

.form-actions {
    display: flex;
    justify-content: flex-end;
    gap: 1rem;
    margin-top: 2rem;
}

When to Use CSS Grid

1. Page Layouts

Creating overall page structure with header, sidebar, content, and footer:

.page-layout {
    display: grid;
    grid-template-areas:
        "header header"
        "sidebar main"
        "footer footer";
    grid-template-columns: 250px 1fr;
    grid-template-rows: auto 1fr auto;
    min-height: 100vh;
}

.header {
    grid-area: header;
}
.sidebar {
    grid-area: sidebar;
}
.main {
    grid-area: main;
}
.footer {
    grid-area: footer;
}

/* Responsive layout */
@media (max-width: 768px) {
    .page-layout {
        grid-template-areas:
            "header"
            "main"
            "sidebar"
            "footer";
        grid-template-columns: 1fr;
    }
}

2. Image Galleries

Complex photo layouts with varying sizes:

.gallery {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    grid-auto-rows: 200px;
    gap: 1rem;
}

.gallery-item {
    border-radius: 8px;
    overflow: hidden;
    transition: transform 0.3s ease;
}

.gallery-item:hover {
    transform: scale(1.05);
}

/* Featured items span multiple cells */
.gallery-item.featured {
    grid-column: span 2;
    grid-row: span 2;
}

.gallery-item.wide {
    grid-column: span 2;
}

.gallery-item.tall {
    grid-row: span 2;
}

3. Dashboard Layouts

Complex admin interfaces with multiple widgets:

.dashboard {
    display: grid;
    grid-template-columns: repeat(12, 1fr);
    grid-auto-rows: minmax(120px, auto);
    gap: 1.5rem;
    padding: 2rem;
}

.widget {
    background: white;
    border-radius: 8px;
    padding: 1.5rem;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.widget-stats {
    grid-column: span 3;
}
.widget-chart {
    grid-column: span 6;
    grid-row: span 2;
}
.widget-recent {
    grid-column: span 3;
    grid-row: span 2;
}
.widget-calendar {
    grid-column: span 4;
}
.widget-tasks {
    grid-column: span 8;
}

/* Responsive adjustments */
@media (max-width: 1024px) {
    .dashboard {
        grid-template-columns: repeat(6, 1fr);
    }

    .widget-stats {
        grid-column: span 2;
    }
    .widget-chart {
        grid-column: span 6;
    }
    .widget-recent {
        grid-column: span 6;
    }
}

@media (max-width: 768px) {
    .dashboard {
        grid-template-columns: 1fr;
    }

    .widget {
        grid-column: span 1;
    }
}

Combining Both: Hybrid Layouts

Often, the best approach is using both together:

/* Grid for overall layout */
.app-layout {
    display: grid;
    grid-template-areas:
        "header"
        "main"
        "footer";
    grid-template-rows: auto 1fr auto;
    min-height: 100vh;
}

/* Flexbox for header navigation */
.header {
    grid-area: header;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
}

/* Grid for main content sections */
.main {
    grid-area: main;
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 2rem;
    padding: 2rem;
}

/* Flexbox for article content */
.article-content {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

/* Flexbox for sidebar widgets */
.sidebar {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

Performance Considerations

Flexbox Performance Tips

/* Avoid unnecessary flex calculations */
.flex-container {
    display: flex;
}

/* Instead of flex: 1 1 auto on every item */
.flex-item {
    flex: 1;
}

/* Use specific values when possible */
.flex-item-fixed {
    flex: 0 0 200px; /* Don't grow, don't shrink, 200px base */
}

Grid Performance Tips

/* Use fr units instead of percentages when possible */
.grid-container {
    display: grid;
    grid-template-columns: 1fr 2fr 1fr; /* Better than 25% 50% 25% */
}

/* Avoid excessive auto-placement calculations */
.grid-explicit {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    grid-template-rows: repeat(3, 200px); /* Explicit is faster than auto */
}

Accessibility Considerations

Maintain Logical Source Order

/* Grid allows visual reordering without changing HTML */
.accessibility-grid {
    display: grid;
    grid-template-areas:
        "nav main"
        "nav aside";
}

/* But ensure HTML order makes sense for screen readers */

<!-- Good: Logical source order -->
<div class="accessibility-grid">
    <nav>Navigation (comes first in HTML)</nav>
    <main>Main content (comes second)</main>
    <aside>Sidebar (comes third)</aside>
</div>

Focus Management

/* Ensure focus indicators work with layout */
.flex-nav a:focus,
.grid-item:focus {
    outline: 2px solid #007acc;
    outline-offset: 2px;
}

/* Consider focus order with visual reordering */
.grid-reordered {
    display: grid;
    grid-template-columns: 1fr 1fr;
}

.grid-reordered .item-1 {
    order: 2;
}
.grid-reordered .item-2 {
    order: 1;
}

Decision Framework

Choose Flexbox When:

Working with a single dimension (row or column)
Content size determines layout
You need items to grow/shrink based on available space
Building navigation bars, button groups, or form controls
Creating equal-height columns

Choose CSS Grid When:

Working with two dimensions (rows and columns)
Layout structure is predetermined
You need precise control over item placement
Building page layouts, image galleries, or dashboards
Creating complex responsive layouts

Use Both When:

Building complex applications with multiple layout needs
Grid for overall structure, Flexbox for component internals
You need the best tool for each specific layout challenge

Conclusion

CSS Grid and Flexbox are complementary tools, not competing ones. Understanding their strengths helps you choose the right approach for each layout challenge. Grid excels at two-dimensional layouts and overall page structure, while Flexbox shines for one-dimensional arrangements and component-level layouts.

The future of CSS layout is bright with both tools in your toolkit, allowing you to build more robust, flexible, and maintainable user interfaces.