Bianconi · Annals of human biology 2013 · mathematical modeling and literature-based estimation · n=?

An estimation of the number of cells in the human body.

Cited 1014 times in the scientific literature.

Level 5 - mechanism / opinion, no new human data

Theoretical calculation and mathematical modeling based on literature review (graded Level 5 by design analogy).

PubMed 23829164 · doi:10.3109/03014460.2013.807878 · record verified 2026-08-26

What was done

The authors conducted a systematic calculation to estimate the total cell count of a standard human adult organism and its individual organs using bibliographical review and mathematical modeling approaches.

What was found

Calculations across a variety of organs and cell types yielded an estimated total human body cell count of 3.72 × 10^13 (approximately 37.2 trillion cells).

Why it matters

This study provides a structured, literature-backed calculation to replace widely circulated, uncited estimates of total human cell count that previously spanned four orders of magnitude (10^12 to 10^16).

Limits

The calculation is a theoretical and mathematical model based on secondary literature rather than direct experimental measurement. The abstract notes that these figures represent partial data across selected organs and cell types rather than an exhaustive direct census.

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