box-sizing
box-sizing is a CSS property in the Size category. Controls element dimensions and intrinsic sizing behavior. The syntax is box-sizing: content-box | border-box. A typical example: box-sizing: border-box; It is commonly applied to markup such as <div class="demo">Sample</div> Browser support: Chrome 4+, Firefox 3.5+, Safari 3.1+, Edge 12+. A close relative is contain-intrinsic-size, which controls element dimensions and intrinsic sizing behavior. A close relative is block-size, which controls element dimensions and intrinsic sizing behavior. A close relative is inline-size, which controls element dimensions and intrinsic sizing behavior. More about this category: CSS sizing properties for width, height, min/max dimensions. Related Size entries: contain-intrinsic-size, block-size, inline-size, interpolate-size, min-block-size, max-block-size, min-inline-size, max-inline-size. This page is part of the free CSS Reference documentation covering 841+ properties, selectors, functions, and at-rules, each with syntax, values, examples, and browser support. You can look up any other entry from the search page or return to the CSS Reference homepage.