The Sun is about --- billion years old.

The Sun is approximately 4.5 billion years old, having formed from the gravitational collapse of a region within a large molecular cloud about 4.6 billion years ago. This age estimate is based on radioactive dating of meteorites and analysis of the Sun's composition and evolution models. The Sun is currently in the main sequence phase of its lifecycle and is expected to remain stable for another 5 billion years before expanding into a red giant.