Definite size

A size known without laying out the contents.

What is a definite size?

A definite size is one the browser can work out without laying out the contents, like 300px or 50% of a fixed-size parent.

.panel { height: 400px; }
.panel .inner { height: 50%; }   /* works: 50% of a definite height */

Level: Master · More CSS terms at this level

Updated September 27, 2026