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People and human anatomy

Human brain

The human brain is the organ that processes sensory information and coordinates thought, memory, movement and many body functions.

Also known as: adult human brain

How big is it?

15 cm · representative front-to-back length

Also 5.906 in

Representative front-to-back length · defined specimen
Typical recorded range: 14 cm to 17 cm.

Scale illustration of the human brain, showing the recorded representative front-to-back length.
Recorded representative front-to-back length: 15 cm.

A little perspective

Human brain vs Feather star: length comparison

The front-to-back length of the human brain is approximately equal to the arm-tip span of a feather star.

Scale
Human brain

The human brain is the organ that processes sensory information and coordinates thought, memory, movement and many body functions.

15 cmRepresentative front-to-back length
0 - shared origin
Feather star

A feather star is a marine crinoid with multiple feathery arms used for filter feeding and movement on the sea floor.

15 cmDefined arm-tip span
0 - shared origin

Both rulers start at the same zero and share one linear scale. Artwork keeps its original proportions.

Measurements, assumptions & sources +

Human brain

Representative front-to-back length: 15 cm; defined specimen; range 14 cm–17 cm.

A defined adult-brain specimen 15 cm front to back and 1.4 kg. Brain size and mass vary by person; these values are comparison anchors, not health benchmarks.

Defined examples — our methodology

The marked representative front-to-back length is calibrated. Unmeasured illustration details are representative.

Feather star

Defined arm-tip span: 15 cm; defined specimen; range 8 cm–30 cm.

A defined 15 cm feather star measured across its spread arm tips. Species, arm count and posture vary; this span includes the feathery arms and excludes detached cirri.

Smithsonian Ocean — Crinoids

The marked defined arm-tip span is calibrated. Unmeasured illustration details are representative.

Use the visual comparison to explore its scale, then check the measurements and sources.

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Why this measurement?

Why we use 15 cm

We compare the front-to-back length of the human brain. This is an illustrative comparison value, not a claim that every example is the same. The recorded range is 14 cm to 17 cm.

A defined adult-brain specimen 15 cm front to back and 1.4 kg. Brain size and mass vary by person; these values are comparison anchors, not health benchmarks.

The marked horizontal span follows the measured feature, not the edges of the image. How calibrated comparisons work →

Explore people and human anatomy →

Recorded properties

Dimensions and measurements

PropertySelected valueRecorded rangeBasis
15 cm14 cm to 17 cmdefined specimen
1.4 kg1.2 kg to 1.6 kgrepresentative

Around this scale

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Compare examples with lower, similar and higher values. Each card names the measurement being compared.

Sources and method

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The source records and measurement method remain available for inspection.

Read the measurement and artwork methodology →

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