The age of the universe is currently estimated to be approximately 13.8 billion years. This age is based on scientific observations and measurements, including the study of cosmic microwave background radiation, the Hubble Space Telescope's observations of the rate of expansion of the universe, and the measurement of the abundance of certain elements.
The most widely accepted model for the origin and evolution of the universe is the Big Bang theory. According to this theory, the universe began as an extremely hot and dense state around 13.8 billion years ago. It has been expanding and cooling ever since. The age of the universe is derived from the measurement of the cosmic microwave background radiation, which is a remnant of the hot, early phase of the universe.
It's important to note that the age of the universe is subject to refinement as our observational techniques and measurements improve. However, the currently accepted value of approximately 13.8 billion years has been widely supported by various lines of evidence.