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.

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.
The human brain is the organ that processes sensory information and coordinates thought, memory, movement and many body functions.
A feather star is a marine crinoid with multiple feathery arms used for filter feeding and movement on the sea floor.
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.
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.
Change your perspective
Put it next to…
Choose a suggestion to redraw the comparison, or open its page to learn what it is.
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 →
Recorded properties
Dimensions and measurements
| Property | Selected value | Recorded range | Basis |
|---|---|---|---|
| 15 cm | 14 cm to 17 cm | defined specimen | |
| 1.4 kg | 1.2 kg to 1.6 kg | representative |
Around this scale
Explore nearby values.
Compare examples with lower, similar and higher values. Each card names the measurement being compared.
Nearest lower valuePeople and human anatomyHuman heart12 cmRepresentative long axisA human heart is a muscular organ that pumps blood through the circulatory system.
Around the same scaleLiving thingsFeather star15 cmDefined arm-tip spanA feather star is a marine crinoid with multiple feathery arms used for filter feeding and movement on the sea floor.
Nearest higher valueEveryday objectsBroccoli head16 cmDefined crown diameterA broccoli head is the compact, edible crown of the broccoli plant, consisting of clustered green flower buds.Sources and method
Want to check the number?
The source records and measurement method remain available for inspection.
- Cleveland Clinic — BrainAdult brain anatomy and a mass around three pounds; the atlas uses a representative 1.4 kg specimen.
- Defined examples — our methodology
There’s always another scale






