Eidolon Hit Points

[Jericho Valdor]

How does the summoner eidolon hit points increase with pfs rules? I am thinking it increases the same as the summoner's being half its hit die which is d10 plus 1 plus con.

[Starglim]

As for an animal companion: average of each hit die + CON modifier. Recalculate the total, then round, whenever its hit dice increase.

[Artanthos]

5.5 + Con per hit die. Round down.

[Dukeh555]

Phew, might not have been the one asking, but I'm glad you add the con modifier. When I saw eidolon 5.5 per hit die, my first thoughts were "Squishiest. Meat shield. Ever."