How many of each there are

Biology's switch count beats silicon's by about a hundred million to one. But at the scale of whole units, the two lists nearly meet.

v3 revised 2026-09-15 Column format with imagery; the ladders read side by side rather than as a table. v2 ›

Read the two columns down. Where a row has no fair counterpart it is left visibly empty rather than filled — a bad pairing costs more credibility than a gap does.

Lifecounted by census
Computinginferred from sales
The switch scale
~10³¹Virus particlesOutnumber cells, and are not cells. They borrow a machine rather than being one.
no counterpart — nothing in computing replicates without a host and is not itself a machine
4–6 × 10³⁰Prokaryotic cellsBacteria and archaea. A 1998 census with published error bars, and it has held up.
≈ 10²²Transistors ever madeNo census exists. Published totals are reconstructions from shipment data, varying by an order of magnitude.
The unit scale
≈ 2.5 × 10²³Human somatic cellsEvery person alive, added together. At the scale above, this rounds to nothing.
≈ 3.4 × 10¹⁰/yrMicrocontrollers shippedA flow, not a stock — nobody publishes the installed base.
8.2 × 10⁹Humans
≈ 7 × 10⁹Smartphones in useThe one row on this page that nearly matches. Within a factor of two, reached in about fifteen years.
The organising scale
8.7 × 10⁶Eukaryotic species±1.3 million, and roughly 86% of land species are still undescribed.
≈ 3–4 × 10⁸Registered businessesThe nearest thing to a species count, and not very near — definitions vary by jurisdiction more than the figure does.
no counterpart — biology has no artefact that exists only while it is being paid for
≈ 10⁷/yrServers shippedDiscrete GPUs in the tens of millions. Both are flows.
Switching elements on Earth
≈ 100,000,000 : 1
Prokaryotic cells number 4–6 × 10³⁰. Transistors ever manufactured are usually put near 10²². Biology leads by roughly eight orders of magnitude — and the silicon figure is the shakier of the two by a wide margin.
What these figures count
counts
Stocks where a stock exists, flows where only a flow is published. The microcontroller and server rows are annual shipments, not installed base; the two differ by roughly the service life.
excludes
Eukaryotic cells other than human. Plants dominate the biomass, but a defensible global eukaryotic cell count does not exist, so none is quoted.
uncertainty
The cell figure is a census with published error bars. The transistor figure has no equivalent. Business counts vary by more still, depending on what registration means in each jurisdiction.
the trap
A transistor and a cell are not comparable units. A transistor switches; a cell metabolises, repairs, replicates and computes. If anything the comparison flatters silicon, by counting each of biology's processors as a single switch.

The one row that nearly matches

Everything here is orders of magnitude apart except one line: 8.2 billion people, and roughly 7 billion smartphones in use. Within a factor of two.

That is the only place in this series where the two substrates arrive at the same number, and it took about fifteen years.

The asymmetry is the finding

It is worth sitting with the fact that we know the number of bacteria on Earth better than we know the number of transistors. One was counted by a deliberate scientific census with published error bars. The other is inferred from sales.

That asymmetry recurs throughout this series. Biology has been measured by people trying to establish a fact; computing is mostly measured by people trying to sell something or report a quarter.

Sources