Animal Companion Health

[TikiCyborg]

At level one, an animal companion has 2 HD. Is the health for AC's calculated the same was as players, where the first HD is full and the rest are half, or are both half?

For Example: AC with a 2d8 HD, would the health come out to 10 or 13? (not counting any con)

[leo1925]

I am pretty sure that animal companions don't get full hit points at first hit die.
Additionaly it's 9 hitpoints not 10. (average of a d8 is 4.5, 4.5 times 2 equals 9)

[Some call me Tim]

leo1925 wrote:

I am pretty sure that animal companions don't get full hit points at first hit die.

Additionaly it's 9 hitpoints not 10. (average of a d8 is 4.5, 4.5 times 2 equals 9)

This is the official method for Pathfinder Society per Joshua Frost.

Generally, full hit points are given only for a PC class level. Monsters with racial hit dice or creatures with NPC class levels don't get full hit points from the first HD and use the above method.

[D'Vit S'Zuké]

Joshua Frost link is blown away due to non-PURL conversion of the paizo site.

The formula that seems to work for all NPC I tested against is:

HIT_POINTS = FLOOR(HIT_DICE*(4.5+CON_BONUS))

See this calculator for an example.
https://jsfiddle.net/ledlogic/2su4otga/

[BigNorseWolf]

Linky

How do I determine hit points for my animal companion, eidolon or other companion creature with a listed number of Hit Dice?

Companion creatures receive the average result on each Hit Dice. For example, animal companions have d8 Hit Dice, which has an average of 4.5. Multiply 4.5 by the number of Hit Dice your animal companion has and round down to determine how many hit points it receives from its Hit Dice. Next, add in appropriate bonuses from its Constitution modifier, feats, and so on.

[blahpers]

NPCs always use average hit points per hit die. Animal companions are NPCs.

Sources:

1. Every Paizo-published NPC stat block I've ever seen, including animal companions
2. The iconic druid PC stat block (in which Lini's first hit die is maximized but Droogami's first hit die is not.)