What is the approximate age of the universe according to modern cosmological measurements?

The universe is approximately 13.8 billion years old according to modern cosmological measurements.

Astronomers estimate this age by measuring the universe’s expansion rate, the cosmic microwave background, and the proportions of its chemical elements. Measurements from the Planck space observatory strongly support an age close to 13.8 billion years within the standard Lambda-CDM model.

This figure means the time since the hot, dense early state described by the Big Bang model. It does not mean the universe expanded into empty space from a single location; rather, space itself has expanded everywhere. The observable universe is much larger than 13.8 billion light-years across because light has traveled through expanding space.

A common mix-up is confusing the universe’s age with the age of the Solar System, which is about 4.6 billion years. The oldest known stars formed later than the Big Bang, after the first generations of stars and galaxies developed.