typography
Leading (line height)
The vertical space between lines of text, usually a percentage of the font size – around 145–150% is the common starting point for body text.
Pronounced “ledding” – named for the strips of lead typesetters once wedged between rows of metal type. Too tight and lines feel crowded and hard to track; too loose and a paragraph stops reading as one unit.
The working default: body text at roughly 1.45–1.5× the font size (16px text → ~24px line height), loosening slightly for long dense passages, tightening for large display headings – big type needs proportionally less air between lines. Treat it as a solid default rather than a fixed law; mature type systems bake a specific line height into each text style.