lineHeight

Line height is the vertical distance between the baselines of successive lines of text. In typography it determines how much space sits between lines and thus the overall density of a block of text. The term leading, from traditional printing, refers to the thin strips of metal placed between lines; line height is the modern digital equivalent that governs line spacing.

In digital typography, line height is commonly controlled by software and web technologies. In CSS the line-height property sets this spacing. Values can be unitless, which act as a multiplier of the element’s font size, or explicit lengths such as px, em, or rem. Unitless values inherit and scale with font size across headings and body text, while lengths fix the spacing regardless of font size.

Good line height improves readability by creating comfortable white space between lines. For body text on the web, common guidance places line-height around 1.4 to 1.6 times the font size; print design often uses about 1.2 to 1.5, depending on typeface and column width. Too-tight line height can hinder reading, whereas excessive spacing can disrupt the document’s vertical rhythm and cohesion.

Line height interacts with font metrics, letter height, and line length, and should adapt to different fonts, sizes, and languages. Accessibility considerations favor sufficient vertical spacing to aid readability for users with vision impairments. Designers test line height across devices and adjust to maintain a consistent and legible vertical rhythm.

Understanding line height helps control legibility and tone in both print and digital typography.