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Hair vs Red blood cell: length comparison

The diameter of a hair is about 9.33 times the characteristic size of a red blood cell. Selected basis: an example for Hair; a representative value for Red blood cell; approximate values.

Hair
Diameter
Red blood cell
Characteristic size
Scale
Hair
70 µmDiameter
0 - shared origin
Red blood cell
7.5 µmCharacteristic size
0 - shared origin

The ring marks the true-scale position of a red blood cell; it does not show its width. Only the inset is enlarged (×59.7).

Both rulers start at the same zero and share one linear scale. Artwork keeps its original proportions. Horizontal rulers compare the selected spans; vertical brackets also identify height on the artwork.

In perspective9.33 times
Measurements, assumptions & sources

Hair

70 µm - Diameter; example.

A hair is a slender strand of protein that grows from the skin of humans and other mammals.

A 70 µm diameter example; hair thickness varies.

Defined examples — our methodology

Red blood cell

7.5 µm - Characteristic size; representative.

A red blood cell is a specialised blood cell that transports oxygen using haemoglobin. Mature human red blood cells are flexible, disc-shaped cells.

A chosen 7.5 µm human red-blood-cell diameter. Real cells vary and deform.

University of Utah — Cell size and scale

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Hair vs Red blood cell