Bacterium
A bacterium is a single-celled microorganism without a membrane-bound nucleus. Different bacterial species have very different forms and sizes.
How big is it?
2 µm long
Length · example
A little perspective
Bacterium vs Platelet: length comparison
The diameter of a platelet is about 1.5 times the length of a bacterium.
A platelet is a small blood-cell fragment that helps form clots and stop bleeding after a blood vessel is damaged.
Both rulers start at the same zero and share one linear scale. Artwork keeps its original proportions.
Measurements, assumptions & sources +
Bacterium
Length: 2 µm; example.
A 2 µm long illustrative bacterium. Species and growth conditions vary.
Defined examples — our methodology
The marked length is calibrated. Unmeasured illustration details are representative.
Platelet
Representative diameter: 3 µm; representative; range 2 µm–4 µm.
A representative inactive human platelet about 3 µm across. Platelets vary in size and change shape dramatically when activated; the illustration is a resting schematic.
University of Utah — Cell size and scale
The marked representative diameter is calibrated. Unmeasured illustration details are representative.
Use the visual comparison to explore its scale, then check the measurements and sources.
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Choose a suggestion to redraw the comparison, or open its page to learn what it is.
Why this measurement?
Why we use 2 µm
We compare the length of a bacterium. This is an illustrative comparison value, not a claim that every example is the same.
A 2 µm long illustrative bacterium. Species and growth conditions vary.
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 |
|---|---|---|---|
| 2 µm | Not recorded | example | |
| 1 pg | Not recorded | defined specimen |
Around this scale
Explore nearby values.
Compare examples with lower, similar and higher values. Each card names the measurement being compared.
Nearest lower valueMicroscopic objectsBacteriophage T4200 nmHead-to-tail lengthBacteriophage T4 is a virus that infects bacteria.
Nearest higher valueMicroscopic objectsPlatelet3 µmRepresentative diameterA platelet is a small blood-cell fragment that helps form clots and stop bleeding after a blood vessel is damaged.Sources and method
Want to check the number?
The source records and measurement method remain available for inspection.
More ways to see it
Curated comparisons
There’s always another scale
Follow your curiosity.
MicroscopicPlatelet3 µmA platelet is a small blood-cell fragment that helps form clots and stop bleeding after a blood vessel is damaged.
MicroscopicYeast cell5 µmYeast is a group of single-celled fungi.
MicroscopicRed blood cell7.5 µmA red blood cell is a specialised blood cell that transports oxygen using haemoglobin.
MicroscopicDust particle10 µmDust is a mixture of tiny solid particles from sources such as soil, fibres, skin and pollen.
MicroscopicCell10 µmA cell is the basic structural unit of living organisms.
PeopleSperm cell50 µmA sperm cell is a male reproductive cell with a compact head, energy-producing midpiece and a flagellum used for movement.MicroscopicBacteriophage T4200 nmBacteriophage T4 is a virus that infects bacteria.
PeopleHair70 µmA hair is a slender strand of protein that grows from the skin of humans and other mammals.A closer look