Miller's Law

People can keep only a handful of things in mind at once, so show the few that matter.

People hold ~7±2 items in working memory. Surface the few that matter.

Miller's Law, side by side

Working memory holds a few chunks, not many items. Group a long string and it becomes memorable.

How to apply it

Use AI for summarization and prioritization, not decoration.

Miller's Law in practice: a concrete example

Why phone numbers are grouped

Nobody remembers 1234567890, but 123-456-7890 is easy, because each chunk fits comfortably in working memory. The same trick makes a settings page usable: group twenty options into four labelled sections and people hold the four sections in their head, not the twenty items. The chunks are what matter, not the raw count.

Common Miller's Law mistakes

Treating “7” as a hard cap on menu items or nav links. The real lesson is chunking, not a magic number.
Long, unbroken forms or strings of digits with no visual grouping to lean on.
Forcing users to carry information across steps from memory instead of keeping it on screen. Favour recognition over recall.

When Miller's Law doesn't apply

Working-memory limits apply to what users must hold in their head, not to lists they can read at leisure. A 30-item search result is fine because it's all visible and scannable. A 30-field form completed from memory is not. Don't cut scannable content to chase a number.

Practise it on a real challenge

SaaS Dashboard — 14 charts, no clear signal

A SaaS dashboard is overwhelming: 14 charts, 6 filters, no clear primary metric.