Given our highly limited understanding of the universe, it’s presently impossible to know. However, current estimates suggest there’s roughly 1,000,000,000,000,000,000,000,000 stars in the universe – that’s 1 septillion in the US numbering system, or 1 quadrillion according to the European system.
Source and further details: https://www.space.com/26078-how-many-stars-are-there.html