Question

How many AU is the universe across?

Answer 1

At least 1.74 million billion AU and utmost 5,85 million billion AU.

Explanation:

Using Hubble constant, the observable universe is at least 13.8 X 2 =

27.6 billion light years across, and in AU unit, this is

27.6 X 62900 billion AU = 1.74 million billion AU.

Further research reports reach an estimate 93 billion light years

and this is 93 X 62900 billion AU = 5.85 million billion AU.

Reference:
http://www.bbc.com/earth/story/20160610-it-took-centuries-but-we-now-know-the-size-of-the-universe