Red blood cell
A red blood cell is a specialised blood cell that transports oxygen using haemoglobin. Mature human red blood cells are flexible, disc-shaped cells.
How big is it?
7.5 µm across
Characteristic size · representative
A little perspective
Dust particle is about 1.33 times larger on this measurement.
Dust particle: Dust is a mixture of tiny solid particles from sources such as soil, fibres, skin and pollen.
Measurements, assumptions & sources +
Red blood cell
A chosen 7.5 µm human red-blood-cell diameter. Real cells vary and deform.
University of Utah — Cell size and scale
The marked characteristic size is calibrated. Unmeasured illustration details are representative.
Dust particle
A chosen 10 µm particle. Dust is a mixture, not a single size or material.
University of Utah — Cell size and scale
The marked characteristic size is calibrated. Unmeasured illustration details are representative.
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Why this measurement?
Why we use 7.5 µm
For comparison, this page uses characteristic size. This is labelled representative; the central value is useful for comparison, while real values or measurement solutions can vary.
A chosen 7.5 µm human red-blood-cell diameter. Real cells vary and deform.
The marked horizontal span follows the named feature; transparent margins and unmeasured details do not alter it. How calibrated comparisons work →
Recorded properties
Red blood cell dimensions and measurements
| Property | Selected value | Recorded range | Basis |
|---|---|---|---|
| 7.5 µm | Not recorded | representative | |
| 100 pg | Not recorded | defined specimen |
Around this scale
Go smaller. Go bigger.
These links use compatible length records, ordered around the selected value.
Nearest lower value · MicroscopicYeast cell5 µmYeast is a group of single-celled fungi.
Around the same scale · MicroscopicDust particle10 µmDust is a mixture of tiny solid particles from sources such as soil, fibres, skin and pollen.
Nearest higher value · Microscopic10 µm cell10 µmA cell is the basic structural unit of living organisms.Sources and method
Want to check the number?
The source records and measurement method remain available for inspection.
- University of Utah — Cell size and scaleApproximate biological size regimes. Atlas specimens and geometric assumptions are individually labelled.
- Defined examples — our methodology
More ways to see it
Curated comparisons
There’s always another scale
Follow your curiosity.
Living thingsHoneybee1.5 cmA honeybee is a social insect that lives in a colony and gathers nectar and pollen from flowers.
Living thingsSmall ant5 mmAn ant is a social insect that lives in an organised colony, usually with workers, a queen and specialised roles.
Everyday thingsUS quarter2.426 cmA US quarter is a coin worth twenty-five cents, commonly used in United States currency.MicroscopicDust particle10 µmDust is a mixture of tiny solid particles from sources such as soil, fibres, skin and pollen.MicroscopicYeast cell5 µmYeast is a group of single-celled fungi.Microscopic10 µm cell10 µmA cell is the basic structural unit of living organisms.
MicroscopicPlatelet3 µmA platelet is a small blood-cell fragment that helps form clots and stop bleeding after a blood vessel is damaged.
PeopleSperm cell50 µmA sperm cell is a male reproductive cell with a compact head, energy-producing midpiece and a flagellum used for movement.