The Milky Way Galaxy is estimated to contain between 100 billion and 400 billion stars. For a more conservative estimate, astronomers often use a figure of about 200 billion stars in the Milky Way.
As for the total number of stars in all galaxies, it's challenging to provide an exact number due to the vastness of the universe and the limitations of current observational capabilities. However, based on current knowledge and observations, astronomers estimate that there are roughly 100 billion to 2 trillion galaxies in the observable universe.
Given that the Milky Way is just one galaxy among many, the estimated number of stars in all galaxies would be mind-bogglingly large. A rough estimate of the total number of stars in all galaxies is around 10^24 (1 septillion) or more. It's important to note that this estimation includes all types of stars, ranging from massive stars to smaller, dimmer ones.