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Cells in the body

Cells in the body
About 36 trillion, of which roughly 80% are red blood cells.

Cells are the structural and functional units of the body, differentiated into around 200 distinct types.

The numbers

Total cells
about 36 trillion
Red blood cells
about 80% of the count
Bacterial cells carried
about 38 trillion
Distinct cell types
roughly 200

Worth knowing

Red blood cells dominate the count while contributing little mass, because they are small and numerous. By mass, muscle and fat cells dominate. A 2016 estimate put human and bacterial cell counts at roughly parity — about 30 trillion each — with the bacteria concentrated almost entirely in the colon.

A common claim that is wrong

The claim that bacteria outnumber human cells ten to one is obsolete. It traced to a 1972 estimate never intended as precise; careful counting puts the ratio close to 1:1.

Structural reference only — this is not medical advice, and individual variation in every figure here is substantial. Anything concerning your own health belongs with a clinician rather than a reference page.

Common questions

What does the cells in the body do?
Cells are the structural and functional units of the body, differentiated into around 200 distinct types..
Cells in the body — key numbers
Total cells: about 36 trillion. Red blood cells: about 80% of the count. Bacterial cells carried: about 38 trillion. Distinct cell types: roughly 200.
Is it true that…
The claim that bacteria outnumber human cells ten to one is obsolete. It traced to a 1972 estimate never intended as precise; careful counting puts the ratio close to 1:1.

Related pages

Sources

  1. Typical range compiled from manufacturer specifications — At One Place

How these figures are compiled and checked