looking for what size wire do i need to put in a 100 amp sub panel with a 150'run off a 400 amp service. new panel will run 60 amp hot tub and sonme lights and ceiling dfans
I would say 1/0 aluminum from the wire size calculator. Any smaller than that and you'll have significant voltage drop.
You'll need 4 wires - two hots, 1 neutral and 1 ground.
There are two ways to go.
Lay a conduit, and have individual wires going through the conduit. Expensive initial construction, but you can obtain 1/0 wires as individual THWN wires at 50 cents a foot (x4 = $2.00/foot). This also allows adding other stuff such as a switched lighting circuit. You can't put data in a power conduit, though. Depending on the type of conduit, conduit can be the ground, which eliminates one wire.
use multi-conductor cable. This is a pre-made cable that has all 4 wires wrapped in a single outer sheath. (this bundle will be rather stiff.) Trouble is, multi-conductor cables are not made in every size (or not kept in stock by distributors). What's more, you must use a type of cable (SER, UF, USE etc.) that is correct for your installation route. This limits your selection further, and you could wind up having to go as big as 4/0 ($4/foot).
I often have to go with a larger cable than the calculator said, because my distributor simply doesn't stock my correct size. This is only a problem with multi-conductor cable; single conductor THWN is generally available in every size if you're working in conduit.