Red blood cell
7.7 µm
Disc diameter
A human red blood cell: a disc dimpled in the middle. About 7.7 µm across.
Published
How big is that?
7.7 µm is 11% of the width of a human hair.
Red blood cell is the 5th smallest of the 32 Tiny Worlds objects, and the 5th smallest of the 172 objects across all five SizeItUp games.
Size comparison
To scale, smallest to largest: Red blood cell in orange beside the Tiny Worlds objects nearest in size, in teal.
| Object | Size | vs Red blood cell |
|---|---|---|
| Cryptosporidium (Oocyst)The tough egg-like stage of a waterborne parasite, with four sporozoites inside. | 4.8 µm across | 62% of the size |
| Yeast cell (Baker's yeast)A single cell of the yeast that raises bread and brews beer. | 6 µm long | 78% of the size |
| Red blood cell | 7.7 µm across | – |
| Neutrophil (White blood cell)The most common white blood cell, with its lobed nucleus. | 10.5 µm across | 1.4× bigger |
| Giardia (Trophozoite)The single-celled gut parasite whose two nuclei look like eyes. | 15 µm long | 1.9× bigger |
In other units
| Micrometres | 7.7 |
|---|---|
| Millimetres | 0.0077 |
| Metres | 0.000008 |
How it's measured
Disc diameter. University of Alabama at Birmingham pathology.
Sources
- peir.path.uab.edu: UAB PEIR histology, chapter 7: red blood cells average 7.7 μm in diameter.
- europepmc.org (supporting): Biosensors 13:117: about eight µm in diameter.
Checked against the source on .
Could you have guessed it by eye?
Red blood cell is one of the objects in Tiny Worlds, a daily size comparison game: you stretch a shape to the size you think is right beside one you know.