People and human anatomy

Index finger

The index finger is the second finger of the human hand, located between the thumb and the middle finger.

How big is it?

8 cm long

Also 3.15 in

Length · example

Scale illustration of Index finger, calibrated to its length measurement.
The marked length represents 8 cm.

A little perspective

About the same scale as Sand dollar.

Sand dollar: A sand dollar is a flat, burrowing sea urchin with a rigid, disc-shaped skeleton, often found in sandy coastal waters.

True scale
01
Index finger8 cmLength
02
Sand dollar8 cmDefined test diameter
Both marked spans share one linear scale. Artwork keeps its proportions; poses and surface detail are illustrative.
Measurements, assumptions & sources +

Index finger

An 8 cm long example, not a population average.

Defined examples — our methodology

The marked length is calibrated. Unmeasured illustration details are representative.

Sand dollar

A defined living sand dollar with an 8 cm test diameter and 25 g mass. Species and maturity vary; short spines are included visually but do not define the rigid test span.

Smithsonian Ocean — Sea urchins and sand dollars

The marked defined test diameter is calibrated. Unmeasured illustration details are representative.

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Why this measurement?

Why we use 8 cm

For comparison, this page uses length. This is labelled example: an explicit comparison model rather than a claim that every example has the same value.

An 8 cm long example, not a population average.

The marked horizontal span follows the named feature; transparent margins and unmeasured details do not alter it. How calibrated comparisons work →

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Recorded properties

Index finger dimensions and measurements

PropertySelected valueRecorded rangeBasis
8 cmNot recordedexample

Around this scale

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These links use compatible length records, ordered around the selected value.

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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