Not sure what your trucks payload capacity is, that is the real tale. Should be on the sticker on the door. As another pointed out, subtract from that all passengers, fuel weight, and any add-ons to the truck (bedliner, running boards, toolboxes, etc., etc.,) the remainder is the weight of hitch AND the pin weight of the fiver you can carry.
My F-150 is just on the correct side of the equation. I gotta be careful not to load too much additional beyond what I have already into the 5th. No heavy stuff like generators, extra batteries, etc. for me!
2012 Ford F-150 Eco, Max/Max
Jayco 26.5 RLS, Reese Sidewinder