MillerRule7 [fact] v1.0.0

George Miller's '7 ± 2' (1956): short-term working memory holds approximately 5–9 'chunks' of information at once. Modern revisions (Cowan 2001) suggest the real working-memory limit is closer to 4 chunks.

Human short-term working memory holds approximately 7 ± 2 chunks of information (Miller 1956), with more recent psychometric work converging on a stricter limit of about 4 chunks (Cowan 2001) — a 'chunk' being any unit the brain can recognise as a single meaningful pattern.

Confidence

proven

Applies To

• navigation item count per group / level
• form field count per step
• options in a single dropdown / radio group
• items in a recent-items / breadcrumb list
• dashboards: KPI tile count above the fold

Quantitative

• Miller 1956: 7 ± 2 chunks
• Cowan 2001: ≈ 4 chunks (more conservative)
• Practical Design Floor: ≤ 5 items per visible group avoids working-memory overflow

Counter Conditions

• Chunking — items perceived as a coherent group count as one chunk (e.g., a 10-digit phone number chunked as 3+3+4).
• Long-term memory / chunk recognition for familiar items (typing your own address) bypasses working-memory limits.
• Visual presentation persists on screen — Miller's limit applies to held-in-mind items, not items currently visible.
• Miller himself described the paper's title as 'almost obsessional' — the 7 number is more cultural shorthand than a precise design rule.

MillerRule7 [fact] v1.0.0

George Miller's '7 ± 2' (1956): short-term working memory holds approximately 5–9 'chunks' of information at once. Modern revisions (Cowan 2001) suggest the real working-memory limit is closer to 4 chunks.

Human short-term working memory holds approximately 7 ± 2 chunks of information (Miller 1956), with more recent psychometric work converging on a stricter limit of about 4 chunks (Cowan 2001) — a 'chunk' being any unit the brain can recognise as a single meaningful pattern.

Confidence

proven

Applies To

• navigation item count per group / level
• form field count per step
• options in a single dropdown / radio group
• items in a recent-items / breadcrumb list
• dashboards: KPI tile count above the fold

Quantitative

• Miller 1956: 7 ± 2 chunks
• Cowan 2001: ≈ 4 chunks (more conservative)
• Practical Design Floor: ≤ 5 items per visible group avoids working-memory overflow

Counter Conditions

• Chunking — items perceived as a coherent group count as one chunk (e.g., a 10-digit phone number chunked as 3+3+4).
• Long-term memory / chunk recognition for familiar items (typing your own address) bypasses working-memory limits.
• Visual presentation persists on screen — Miller's limit applies to held-in-mind items, not items currently visible.
• Miller himself described the paper's title as 'almost obsessional' — the 7 number is more cultural shorthand than a precise design rule.

Sources

Confidence

proven

Source

• George A. Miller, 'The Magical Number Seven, Plus or Minus Two', Psychological Review (1956)
• Nelson Cowan, 'The magical number 4 in short-term memory: A reconsideration of mental storage capacity', Behavioral and Brain Sciences (2001)
• Baddeley, A. D., 'Working memory', Science (1992)

Applies To

• navigation item count per group / level
• form field count per step
• options in a single dropdown / radio group
• items in a recent-items / breadcrumb list
• dashboards: KPI tile count above the fold

Quantitative

• Miller 1956: 7 ± 2 chunks
• Cowan 2001: ≈ 4 chunks (more conservative)
• Practical Design Floor: ≤ 5 items per visible group avoids working-memory overflow

Counter Conditions

• Chunking — items perceived as a coherent group count as one chunk (e.g., a 10-digit phone number chunked as 3+3+4).
• Long-term memory / chunk recognition for familiar items (typing your own address) bypasses working-memory limits.
• Visual presentation persists on screen — Miller's limit applies to held-in-mind items, not items currently visible.
• Miller himself described the paper's title as 'almost obsessional' — the 7 number is more cultural shorthand than a precise design rule.