---
name: Large text threshold
slug: large-text-threshold
category: accessibility
status: published
created: 2026-08-21T00:00:00.000Z
modified: 2026-08-21T00:00:00.000Z
definition: The size at which text counts as large for contrast purposes (about
  18pt, or 14pt when bold) and its required ratio drops from 4.5:1 to 3:1.
aliases:
  - name: large-scale text
    source: wcag
  - name: large text
    source: community
  - name: 18pt rule
    source: community
tags:
  - wcag
relations:
  contrastWith:
    - contrast-ratio
    - apca
  variantOf: []
  partOf: []
  seeAlso: []
implementations: []
sources:
  - title: "WCAG 2.2: Contrast (Minimum)"
    url: https://www.w3.org/TR/WCAG22/#contrast-minimum
demo: inline
exhibit: false
useWhen: deciding which contrast number a heading owes
---

Criterion 1.4.3 asks for a [contrast ratio](/contrast-ratio) of 4.5:1, and then makes one
exception: large-scale text needs only 3:1. Large-scale means at least 18 point, or at least 14
point when the text is bold. The reasoning is straightforward, if not quite exact. Bigger
letterforms put more pixels of ink on the page per stroke, so the same measured ratio is easier
to resolve, and the standard buys a little contrast back in exchange for size. At the enhanced
level, 1.4.6, the same split runs one notch tighter: 7:1 normally and 4.5:1 for large text.

The trap is the unit. WCAG states the threshold in points because it was written for a world of
printed style guides, and CSS is authored in pixels. The conversion the specification itself uses
is 1pt equals 1.333px, so 18pt is 24px and 14pt bold is 18.66px, which nobody rounds the same way
twice. Teams routinely convince themselves that a 20px heading is large text. It is not, unless it
is bold. Two more details catch people out. Bold means the weight the browser actually renders,
so a 700 declaration on a family with no bold face may not earn the discount. And the threshold is
about rendered size, so a heading that shrinks at a narrow breakpoint can quietly cross back over
the line while nobody is testing that width.

Two things it is not. [Non-text contrast](/non-text-contrast) is 1.4.11, and its 3:1 applies to
icons, borders, and control boundaries at any size, which is a different criterion that happens to
use the same number. And [APCA](/apca), the candidate replacement algorithm, dissolves the whole
threshold: it treats size and weight as continuous inputs to one lightness contrast calculation
rather than as a switch between two fixed ratios, which is a better model of how reading actually
works and is also why an APCA score cannot be compared to a WCAG one.

Practically, this is the number that decides how much of a palette is usable. It is what makes a
mid-grey legal in a display heading and illegal in the body copy underneath it, and it is worth
knowing before you promise a [conformance level](/conformance-level) on a design that leans on
soft greys. It also has to survive [dynamic type](/dynamic-type): text that a reader has scaled up
crosses into large-scale territory, which means it can only get safer, while a design that hard
codes small sizes to keep a layout intact removes the exception it was relying on.