How many stars are in the universe?

Nobody can count every star, so astronomers estimate the number by multiplying the average number of stars per galaxy by the number of galaxies. Our Milky Way alone contains somewhere between 100 billion and 400 billion stars. The observable universe, the part whose light has had time to reach us, is thought to hold hundreds of billions to a couple of trillion galaxies. That gives a rough total of about 10 to the power of 22 to 10 to the power of 24 stars, with 200 billion trillion a commonly quoted middle figure. By comparison, only about 9,000 stars are bright enough to be seen with the naked eye across the entire sky.