First really big cook coming - advice sought!

50 people? Assuming there will at least be bread.

50 people x 1/3 pound cooked meat means you need 17 pounds of cooked product

at a cook loss of 50%, you need to start with 34 pounds of raw, bone-in pork butts. Maybe a little less if boneless. Assuming 7 pounders, you will need 5 butts.

If there will be other sides and such there you can figure the average person will eat anywhere between 1/4 - 1/3 of a pound of cooked pork. And the general rule of thumb is 50-60% yield from raw pork to cooked pork.

Going with the lower percentage of the yield and bigger amount of serving, to be on the safe side. You are looking at a 50% yield from raw pork to cooked pork and 1/3lb per person.

So 1lb of cook pork will feed 3 people. You are looking at needing 16lbs of cooked pork to feed approximately 48 people. To get to 16lbs of cooked pork, you are going to need 32lbs of raw pork butt to get the 16lbs of cooked pork.

I would get 9.5lb - 10lb pork butts x4 for that cook. That should give you a little bit extra just incase. If you think the people are going to be bigger eaters get a 5th pork butt.

Landarc and aawa have nailed your answer...

The sides are what will make the difference between 1/3 and 1/4 pound per person.

I just did butts for ~50 people a couple weekends back. I had four bone-in butts, total of a little over 35 pounds. I pulled the three largest butts and left the last one whole. Served on Hawaiian brand dinner rolls as sliders. There were LOTS of sides. All of the pork I pulled (probably 28# uncooked) was either eaten or taken at the end of the night. Took the other butt the next day and a smaller group had "leftovers"...

Took 9 hours cook time on my 22.5" WSM at around 280*. Cook thread here:

http://www.bbq-brethren.com/forum/showthread.php?t=193541