vatican in a day
 

is it possible to do the vatican in a day? we only have five days in rome and i am trying to fit it all in. any ideas?

Depending on when you go. If its tourist season, in would be doable, but you'd have to start really early and end late. If off season like I did, it is easy to do.

In May, we walked through St. Peter's square, St. Paul's cathedral, stood in line for and went through the Vatican Museum (including the Sistine chapel), and had a nice lunch, all in a comfortable day. Now keep in mind that my wife and I are both '20-minute tourist' types who do not dawdle. On the other hand I did stand in awe of some room-sized Raphaels for an uncharacteristically long time. But if the crowd size is reasonable and you do keep up the pace, it's comfortable. However, if you prefer to really study the art in the Vatican Museum, then that alone could take 3 days or more.

If you want to see every single item in the Vatican museums

Yes, you can do it pretty easily. I'd start with the Vatican Museums. Follow the shortest path through the Museums to see the highlights, including the Sistine Chapel, exit the chapel via the tour group exit so you wind up at St. Peter's (not St. Paul's) Basilica. You can see the Basilica, including the Treasury, grotto and climbing the dome in two hours or so, if the line for the dome isn't too long. Fitting the Scavi in can be tricky. The Scavi office assigns the times so if you are lucky and get a late afternoon time to visit the Scavi, you can even fit that in.

Re the scavi (excavations beneath St. Peter's): advance reservations are required and appear not to be easy to come by; the process can take a long time. Do a search here on "scavi" to find the link for tickets.

I agree with Grinisa. But with your screen name, you may want to spend more time in the Vatican Museum, and St. Peter's Basilica. You do have the choice of 4 different tours, each allowing you to see as much or as little of the VM as suits you.
Grinisa - Thanks for the clarification of the St. Peter's. I thought I had missed something during my visit.