← Back to properties
CSS Property
box-sizing
SizingControls whether padding and border are included in an element's total width and height.
Syntax
box-sizing: value;
Example
box-sizing: border-box;
Common use cases
- Preventing layout overflow from padding
- Making width calculations predictable
- Universal box model reset
Practical developer insight
border-box is the most predictable box model and is commonly used as a global default — add * { box-sizing: border-box } to every project.