Box-shadow vs Drop-shadow in CSS: Key Differences and Usage

box-shadow adds shadow directly to an element's box, including borders and padding, while drop-shadow applies a shadow to the rendered image of an element, often used with filter. box-shadow works on all elements, but drop-shadow is best for images and SVGs with transparent areas.

Quick Comparison

Here is a quick side-by-side comparison of box-shadow and drop-shadow in CSS.

Feature	box-shadow	drop-shadow
Type	CSS property	CSS filter function
Applies to	Element's box (including borders and padding)	Rendered image of element (including transparency)
Supports multiple shadows	Yes	No
Performance	Generally faster	May be slower due to filter processing
Use case	UI elements, buttons, containers	Images, SVGs, complex shapes with transparency
Syntax complexity	Simple and direct	Requires filter property syntax

Key Differences

box-shadow creates shadows around the rectangular box of an element. This includes the content, padding, and border areas. It can add multiple shadows separated by commas and supports inset shadows inside the box. Because it works on the box model, it does not consider transparent parts inside images or SVGs.

On the other hand, drop-shadow is a filter function applied via the filter property. It creates a shadow based on the visible pixels of the element, respecting transparency. This makes it ideal for images or SVGs with irregular shapes or transparent backgrounds. However, it does not support multiple shadows and can be more performance-intensive.

In summary, box-shadow is great for general UI shadows on rectangular elements, while drop-shadow is better for shadows that follow the shape of images or complex graphics.

Code Comparison

Here is how you add a shadow to a simple box using box-shadow:

css

div {
  width: 150px;
  height: 150px;
  background-color: #4a90e2;
  box-shadow: 10px 10px 15px rgba(0, 0, 0, 0.5);
  margin: 20px;
}

Output

A blue square box with a soft dark shadow offset to the bottom right.

drop-shadow Equivalent

Here is how you add a similar shadow effect using drop-shadow filter on the same box:

css

div {
  width: 150px;
  height: 150px;
  background-color: #4a90e2;
  filter: drop-shadow(10px 10px 15px rgba(0, 0, 0, 0.5));
  margin: 20px;
}

Output

A blue square box with a soft dark shadow offset to the bottom right, shadow follows the shape of the box.

When to Use Which

Choose box-shadow when you want simple shadows around rectangular UI elements like buttons, cards, or containers. It is easy to use, supports multiple shadows, and performs well.

Choose drop-shadow when you need shadows that follow the shape of images, icons, or SVGs with transparent areas. It creates more natural shadows for irregular shapes but can be slower and does not support multiple shadows.

Key Takeaways

box-shadow adds shadows to the element's box and supports multiple shadows.

drop-shadow applies shadows to the visible shape of an element, respecting transparency.

Use box-shadow for UI elements and drop-shadow for images or SVGs.

drop-shadow is a filter and may affect performance more than box-shadow.

box-shadow is simpler and more widely supported for general shadow effects.