The baseline is the invisible line on which characters sit in typography. Letters like a, m, and x rest directly on it. Letters with descenders, like g, p, and y, drop below it. Letters with ascenders, like b, d, and h, rise above the x-height. The baseline anchors the text and keeps it aligned across a line.

Baselines matter for more than single lines of text. In multi-column layouts, aligning baselines across columns creates a subtle rhythm that makes the page easier to read. Designers use a baseline grid, a series of horizontal lines spaced at regular intervals, to align text blocks across a spread or webpage. When baselines are misaligned, the page feels slightly off even if the viewer cannot identify the problem.

Baseline-related terms

• Baseline shift: moving a character up or down from the baseline.
• Baseline grid: horizontal lines for aligning text.
• X-height: the height of lowercase letters without ascenders.
• Descender: the part of a letter that drops below the baseline.

The baseline is invisible, but it does quiet work in every well-set page. Typographers notice when it is wrong. Readers only feel it.