How many stars are in the Milky Way?
Guess before you scroll — the answer is below
The answer
200,000,000,000 stars
Roughly 200B.
The Milky Way holds roughly 200 billion stars. The Gaia mission has precisely mapped about 2 billion of them — around 1% — and that is by far the most detailed star catalogue ever made.
How to get close to this number
Estimate by volume and density. The galaxy is about a hundred thousand light years across, and stars in our neighbourhood sit a few light years apart. Dividing the galactic volume by the volume each star occupies gives a figure in the hundreds of billions, which is the right order.
The mapped fraction in the explanation is the humbling part: the most detailed star catalogue ever made covers around one percent. We have precise positions and motions for two billion stars and estimates for the rest, so the galaxy total is an extrapolation from a small, nearby, selection-biased sample.
The bias matters for how the estimate is built. We can only see stars that are bright enough and not hidden behind dust, and the galactic centre is obscured from our viewing angle — so the count leans heavily on models of how many faint stars exist for each bright one. The number is a model output as much as an observation.
Where this number comes from
| Source | European Space Agency, Gaia mission |
|---|---|
| Figure refers to | 2024 |
| Last checked | |
| Unit | stars |
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.