Calculating hit points per level

[tadkil]

From a design perspective letting players roll their own HP can create mayhem. What happens if a character rolls in the bottom 25% for 3-4 levels? What happens if his peer maxes? The disparity can make designing challenges that are not inordinately lethal very difficult. You can let higher AC items in to harden the skin of low HP players, but you'll find yourself designing to this challenge more than you like.

I have run with both and until 3.0 always had my players roll their HP. I like the average now. Safer for them and easier to manage for the DM.

[Mad Nomad]

I recently came up with some house rules on this.
- For reasons mentioned earlier, pure rolling is too swingy and not really viable.
- Taking average is fine, but takes some of the variability out of it so I didn't like that either.
- Rolling and allowing player to take the roll if it's higher than average or take average if it is lower is common house rule, but it does scew PCs HP higher than game is technically base don.

So to try to keep rolling and variance in the game but remove some of the crazy "swinginess" and risk of rolling really low I adopted these rules.
If normal HD is…

1d6 (normally 4 average): you gain 2+1d4 (now ranges (3-6) avg 4.5)

1d8 (normally 5 average): you gain 3+ 1d4 (now ranges (4-7) avg 5.5)

1d10 (normally 6 average): you gain 4+1d4 (now ranges (5-8) avg 6.5)

1d12 (normally 7 average): you gain 5+1d4 (now ranges (6-9) avg 7.5)

+ Con modifier of course

[JohnD]

I've always done the following:

1st level - maximum HP
2nd level - roll 2 dice taking the higher roll but minimum of 50%+1
3rd level & beyond - roll 2 dice taking the higher roll

It works... still skews to the high end but allows for a few lower rolls.

[damned]

In Castles & Crusades I usually went:
1st: max hp
2nd: 75% rounded up
3rd: 75% rounded up
4th: roll your own