Astronomers dont know the exact number of galaxies in the universe, but the best scientific estimates give a good range.

Current best estimate

Observations from the Hubble Space Telescope suggest there are about 100200 billion galaxies in the observable universe.

Newer research

When scientists analyzed extremely deep images like the Hubble Ultra Deep Field, they realized many faint, distant galaxies are too small or dim to easily detect. Some studies (2016 and later) estimate the real number might be closer to:

2 trillion galaxies in the observable universe.

Why were not sure

1. Telescopes can only see part of the universe (the observable universe).
2. Very distant galaxies are faint or tiny.
3. The universe is expanding, so the most distant ones are harder to detect.

New telescopes like the James Webb Space Telescope are helping astronomers find even more early and faint galaxies, which may change the estimate again.

A mind-blowing comparison

A typical galaxy like the Milky Way contains 100400 billion stars.

So if there are ~2 trillion galaxies, the total number of stars in the observable universe could be around:

1010 stars (thats more stars than grains of sand on Earth).

In short:

• Conservative estimate: 100200 billion galaxies
• Possible total: up to ~2 trillion galaxies in the observable universe.

If you want, I can also explain how scientists actually count galaxies (its a clever trick using tiny patches of sky).