However, it is sometimes used in a more informal way to describe the time it takes for the Sun to complete one orbit around the center of the Milky Way galaxy. This time is estimated to be around 225–250 million Earth years.
So, to answer your question directly, a "cosmic year" (as defined above) is approximately 225–250 million Earth years.
It's important to remember that this is an informal definition and not a universally accepted term.
