---
name: Chunking
slug: chunking
category: accessibility
status: published
created: 2026-08-21T00:00:00.000Z
modified: 2026-08-21T00:00:00.000Z
definition: Breaking content into small labelled pieces, short paragraphs,
  lists, and headings, so a reader can hold one piece at a time instead of the
  whole wall.
aliases:
  - name: content chunking
    source: community
  - name: succinct text
    source: w3c
  - name: visual grouping
    source: community
tags:
  - content-design
  - perception
relations:
  contrastWith:
    - one-thing-per-page
    - cognitive-load
    - plain-language
  variantOf: []
  partOf: []
  seeAlso:
    - proximity
implementations: []
sources:
  - title: "W3C: Keep Text Succinct"
    url: https://www.w3.org/WAI/WCAG2/supplemental/patterns/o3p05-succinct-text/
demo: inline
exhibit: false
useWhen: a dense block has to be read by anyone tired
---

Sixteen digits in a row is one long thing to hold. The same sixteen digits in four groups
is four short things, and four short things are what a person can actually keep in mind
while reading them off a card and typing them into a field. That is the whole mechanism,
and it scales up from a card number to a page: short paragraphs, headings that say what
the next stretch is about, lists instead of comma-strung sentences, and a form broken
into named sections rather than presented as one column of thirty fields.

The number everyone quotes deserves care. George Miller's 1956 paper on the "magical
number seven, plus or minus two" was about absolute judgment and the span of immediate
memory, not about how many links belong in a menu, and Miller was wry about the figure
following him around. Later work puts the working memory span closer to four items, and
the practical reading is simply that fewer, clearer pieces are held better than more,
denser ones. It never licensed a rule that navigation must have seven entries.

Chunking is the cheapest tool against [cognitive load](/cognitive-load), because it
removes effort the design added rather than effort the task requires. It is also the
principle two ordinary components are built out of: a [pin input](/pin-input) is a code
chunked into one box per character, and an [input mask](/input-mask) is a value chunked as
you type it. Formatting a value for display and accepting it unformatted are separate
decisions, and the generous version does both: group the digits on the screen, and let the
reader paste the whole run in unbroken.

Group sizes are conventions worth respecting rather than inventing. Card numbers run in
fours, phone numbers follow the local dialling shape, sort codes and postcodes have forms
readers already know, and a code invented for an email should be split into threes or
fours because that is what people can read back over a phone. In prose the same instinct
means one idea per paragraph and a heading every few of them. The failure mode of
chunking is chunking everything: a page of six-word paragraphs under a heading each is
just as hard to read, because the pieces no longer say how they relate.