How many bacteria live in the human body?
Science brutal Data from 2016
Guess before you scroll — the answer is below
The answer
38,000,000,000,000 bacteria
Roughly 38T.
The best current estimate is about 38 trillion bacteria, most of them in the colon — roughly the same order as the number of human cells, not the ten-to-one ratio that circulated for decades. That older figure traced back to a single 1972 back-of-envelope estimate that nobody checked.
Where this number comes from
| Source | Sender, Fuchs & Milo, PLOS Biology |
|---|---|
| Figure refers to | 2016 |
| Last checked | |
| Unit | bacteria |
Numbers move. If this one has drifted from its source, let us know.
Think you can do better?
Five fresh questions every day. No account needed.