Wolfram|Alpha now does estimations.
Also, it brings back memories to one Friday where we decided to figure out how many Olsen (cubic light years of beer) could theoretically fit in the universe if the universe’s mass was all beer.
Then, we spent a good half hour looking for estimates of the mass of the universe, the density of beer, the exact length of a light year (which in retrospect we should have been able to compute), and probably a bunch of unnecessary units. We then spent a lot of time trying to wrap our semi-drunk minds around doing the computations without screwing up the exponents. Looking at the answer below, I think we got it wrong back then.
Today, we could just do this: http://tinyurl.com/universeofbeer So now you know: the mass of the entire universe is approximately 3900 times the mass of one cubic light year of beer.
