While it's impossible to know for sure the exact size of the entire universe, the observable universe is the portion we can see and study from Earth. This region is estimated to be 93 billion light-years across, meaning it's the largest structure we know of in the cosmos.
It's important to note that the observable universe isn't the entire universe, just the part we can see based on the speed of light and the age of the universe. There might be more beyond our observable horizon, but we have no way of knowing for sure.
