How many men in a us marine boot camp platoon?

Minimum of 41:

3 squads (Sqd) of 13

1 Platoon Sergeant (Plt Sgt)

1 Platoon Commander (Plt Cmndr)

Sqd = 3 Fireteams (FT) of 4 + 1 Sqd leader

FT = 1 FT leader, 1 Rifleman, 1 SAW gunner, 1 Assistant SAW gunner

There can be a Guide, position somewhat similar to Plt Sgt but it is a billet below him. Each platoon will also have a Corpsman assigned to them (Navy personnel, not a Marine)