Design Nomenclature / Systems & Spec
Text spacing
Also called SC 1.4.12, text spacing override, text spacing bookmarklet
WCAG 2.1 SC 1.4.12, Level AA: no content or functionality is lost when the reader overrides line height to 1.5× the font size, spacing after paragraphs to 2×, letter spacing to 0.12×, and word spacing to 0.16×. It tests whether containers give, not whether the defaults were well chosen.
In practice
Read as a recommendation to set those values. It isn't — it is a stress test, and what it catches is fixed-height boxes and text clipped by its own container.
Not to be confused with
- TrackingA uniform adjustment to the space after every glyph in a run — CSS letter-spacing. Size-dependent: display type usually wants negative tracking because the sidebearings were fitted for text, while small caps, all-caps runs and small labels want positive. Body text at text size almost never wants any.
- LeadingThe vertical distance from one baseline to the next. It is set against measure, not in isolation: a long line needs more of it for the eye to find the next line's start, a short line needs less. Under-leaded text merges lines; over-leaded text dissolves the paragraph into stripes.