The age of the universe is estimated to be approximately 13.8 billion years. This value is derived from observations and measurements made by astronomers using various techniques, such as studying the cosmic microwave background radiation, the expansion rate of the universe, and the ages of the oldest known celestial objects.
The current understanding is that the universe originated from a hot, dense state known as the Big Bang around 13.8 billion years ago. This age is based on the best available scientific evidence and observations, but it's important to note that our understanding of the universe's age continues to evolve as new data and techniques become available.