Since the mid-1990s, the working estimate for the number of galaxies in the Universe has been around 120 billion. That number was based largely on a 1996 study called Hubble Deep Field … Researchers pointed the Hubble Space Telescope at a small region of space for a total of ten days. Astrophysicists then counted the galaxies within that narrow field of view and extrapolated the number to the full sky to get to the 120 billion figure.
More recent deep-field studies conducted using Hubble and other telescopes means we now know that the observable Universe contains about two trillion galaxies — more than ten times as many as previously estimated.
Considering that the galaxy we live in, the Milky Way, contains around 100 billion or more stars we can safely assume that the number of stars in the entire universe is a very large number indeed!