Box Shadow vs Drop Shadow: When to Use Each

CSS offers two ways to add shadows to elements: box-shadow and filter: drop-shadow(). While they might seem similar, they behave quite differently.

The Key Difference

The fundamental difference is what they shadow:

Box Shadow Behavior

box-shadow always creates a rectangular shadow matching the element's box model:

.element {

box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);

}

This means:

Drop Shadow Behavior

filter: drop-shadow() respects the actual shape of the content:

.element {

filter: drop-shadow(0 4px 8px rgba(0, 0, 0, 0.2));

}

This means:

When to Use Box Shadow

Choose box-shadow when:

Working with solid rectangular elements

Cards, buttons, and containers work perfectly with box-shadow.

You need spread radius

Box-shadow supports a spread value; drop-shadow doesn't.

box-shadow: 0 4px 8px 2px rgba(0, 0, 0, 0.2);

You want inset shadows

Only box-shadow supports the inset keyword.

You need multiple shadows

While both support multiple shadows, box-shadow syntax is cleaner.

Performance is critical

Box-shadow is generally faster to render.

When to Use Drop Shadow

Choose drop-shadow when:

Working with transparent images

PNGs or WebPs with transparency need drop-shadow for accurate shadows.

Shadowing SVG graphics

Complex SVG shapes shadow correctly with drop-shadow.

Creating text shadows on complex backgrounds

Though text-shadow exists, drop-shadow can create different effects.

Working with clip-path

Elements with clip-path need drop-shadow since box-shadow ignores clipping.

Syntax Comparison

The syntax is slightly different:

Box shadow:

box-shadow: offset-x offset-y blur spread color;

Drop shadow:

filter: drop-shadow(offset-x offset-y blur color);

Note: drop-shadow doesn't support spread or inset.

Practical Examples

Icon with Transparency

For a PNG icon:

.icon {

filter: drop-shadow(0 2px 4px rgba(0, 0, 0, 0.2));

}

Card Component

For a card:

.card {

box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);

border-radius: 8px;

}

Complex Shape

For a star-shaped element:

.star {

clip-path: polygon(...);

filter: drop-shadow(0 4px 8px rgba(0, 0, 0, 0.3));

}

Combining Both

You can use both on the same element for complex effects:

.element {

box-shadow: 0 0 0 4px white;

filter: drop-shadow(0 4px 8px rgba(0, 0, 0, 0.2));

}

Conclusion

Choose box-shadow for most UI elements and drop-shadow when you need shape-aware shadows. Use ShadowSpark to design your box shadows visually and get the CSS code instantly.