ESA - Space Science - Extreme space - How many stars are there in the Universe?: "For the Universe, the galaxies are our small representative volumes, and there are something like 10^11 to 10^12 stars in our galaxy, and there are perhaps something like 10^11 or 10^12 galaxies.
With this simple calculation you get something like 10^22 to 10^24 stars in the Universe. This is only a rough number, as obviously not all galaxies are the same, just like on a beach the depth of sand will not be the same in different places."
