max-width

Definition

The max-width CSS property is used to set the maximum width that an element can have. It restricts the width of the element to a specified value, preventing it from exceeding that limit.

The max-width property accepts various length units, such as pixels (px), percentages (%), viewport width (vw), or the none keyword.

Here’s an example:

.container {
  max-width: 600px;
}

In this example, the .container class sets a maximum width of 600px for the element. If the content inside the element expands beyond this width, it will be automatically truncated or wrapped based on the overflow property.

You can also use other length units or percentage values to set a relative maximum width:

.container {
  max-width: 80%;
}

In this case, the .container class sets a maximum width of 80% of its containing element’s width. This allows the element to adjust its width based on the available space.

The max-width property is useful when you want to limit the width of an element, preventing it from growing beyond a certain point. It is commonly used to control the size and responsiveness of elements, ensuring they fit within their intended layout and viewport.

Syntax

.component {
  max-width: 40rem;
}

Set max-width with absolute units, responsive percentages, or viewport-based lengths depending on the layout needs.

Values

• <length>: fixed sizes using px, rem, em, vh, vw, and other length units.
• <percentage>: resolves against the size of the containing block (for width) or the available height when explicitly defined.
• auto: keeps the browser-calculated size without clamping the item.
• none: removes the upper bound entirely.

Practical Examples

.content {
  width: min(90vw, 70ch);
  max-width: 960px;
}

This pattern keeps copy readable on large screens while still shrinking gracefully on smaller devices.

<div class="grid gap-4 sm:grid-cols-2">
  <div class="space-y-3 rounded-lg border border-slate-200 bg-white p-4 shadow-sm">
    <p class="text-xs font-semibold uppercase tracking-wide text-slate-500">With max-width: 40rem</p>
    <div class="rounded-md border border-dashed border-slate-300 bg-slate-50 p-4 text-sm text-slate-700" style="max-width: 40rem; width: 100%;">
      This panel uses max-width: 40rem, so it stops expanding past that width.
    </div>
  </div>
  <div class="space-y-3 rounded-lg border border-slate-200 bg-white p-4 shadow-sm">
    <p class="text-xs font-semibold uppercase tracking-wide text-slate-500">Without max-width</p>
    <div class="rounded-md border border-dashed border-slate-300 bg-slate-50 p-4 text-sm text-slate-700">
      The panel stretches to fill the grid column.
    </div>
  </div>
</div>

Tips & Best Practices

• Use min()/max()/clamp() to express responsive bounds without relying on many media queries.
• Combine width constraints with margin: 0 auto; to center fixed-width blocks.
• Providing a reasonable max- value prevents content from stretching uncomfortably on ultrawide displays.

Accessibility & UX Notes

Ensure interactive controls remain at least 44px in their tap target size when you constrain dimensions. Strategic max widths also improve readability for long-form copy by keeping line lengths manageable.

Browser Support

Fully supported across modern desktop and mobile browsers. When supporting legacy IE, avoid logical properties such as inline-size unless you supply explicit fallbacks.

Related

• min-width, max-width, min-height, max-height for complementary constraints.
• box-sizing to control whether padding and border are included in the computed size.
• Logical properties (inline-size, block-size) for writing-mode aware layouts.