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Flawed House Rule: Double-Rolling Hit Dice

posted Tuesday, July 17th 2007 by Jonathan Drain
Game DesignThird Edition

I’d imagine that most Dungeon Masters have made their own tweaks and variants to the Dungeons & Dragons game system. The most popular of these “house” rules often spread to games run by other DMs. Unfortunately, popular doesn’t always mean good.

One example of such a flawed rule is double-rolling hit dice, wherein players roll twice for each hit die and take the highest result. I got this one from my former Dungeon Master, and used to use it in my early games. It’s clearly popular among powergamers, and at first sight there’s nothing wrong with the rule.

Mathematics disagrees! Statistically, double-rolling increases the average result of hit dice, making characters tougher. A fighter’s d10 rises from an average 5.5 to 7.15, an increase of 30% before Constitution, and with 16 Constitution still around 20%. The problem with this, as opposed to something like higher ability scores, is that you throw hit points out of whack with everything else in the system. Your saves and offensive abilities are not improved, only your capacity for taking damage.

In this case, it’s especially bad because more hit points has the only effect of letting you last longer and relax a little in combat, taking an element of risk out of the game. This has the effect of making combats last longer and making the game more dull, the latter of which is a Bad Thing. If you scale up the opponents’ hit points by double rolling to compensate, it just exacerbates the effect and makes extra work for yourself, and if you scale up the opponents’ challenge ratings you’ve simply made the game more deadly because your players’ offensive and saves don’t match their hit points.

Beefing up your player characters for its own sake isn’t necessarily good. If it just makes the game easier for your players, it’s not necessarily going to make the game more enjoyable.

Comments

  1. Chris

    July 21st, 2007

    Well, I agree with what you are saying, but what happens to the player who is just plain unlucky and happens to be the group’s ‘tank’. What if he rolls 1 or 2 on his 1d10 hp roll for 2nd and 3rd level? This in its own right is unbalancing. Maybe a compromise would be to have the player roll two hit die rolls and average them. This will change the ‘bell curve’ to produce more average results and thus counter the argument either way. A player would have to be real lucky to get max hp or min hp.

    I have heard all kinds of House Rules on the subject from ½+1, two rolls, and even max past 1st level. I guess it boils down to how the DM wants to run his campaign. For instance, PCs with max HP will run into 6 Orcs instead of 4 for instance.

    Thoughts of a D&D addict,

    Regards

  2. Tom

    August 21st, 2007

    Our GMs usually play that we can choose to have a second roll only if the first result is low relative to the dX eg can reroll a d10 if the first roll is 1, 2 or 3.

    Also, if you reroll you have to take the new result.

    Using your example above, the average for d10 (assuming you always take the reroll) would go from 5.5 to 6.55 – still 20% higher without Con bonuses – but it also doesn’t distort the distribution as much (chance of a 10 is 13% vs 19% under the 2-roll system).

  3. Rob

    September 22nd, 2007

    I DM a house rule in an Eberron campaign where a player can burn an action point for that level if she rolls a 2 or less on a hit die. I don’t know ow it affects my choice of challenges for them but it feels fair enough.

    I have never heard of the “best of two” house rule and I am glad. Your argument makes perfect sense.

  4. JT

    November 15th, 2007

    We had a reasonably detailed argument about this once. After some discussion, we realized the real goal is to improve the bad rolls, i.e., bring up the lowest percentile of characters, while not inflating the average much. Some good methods for accomplishing this are the following (the second is a generalization of poster 2′s approach)

    (1) For dN hit die, roll twice, add a random 0 or 1 (decided, e.g., by rolling d6/4, round down), and divide by 2 (round down). This has the same mean and median as the usual roll dN approach, but substantially reduced variance. Some players don’t like this because it makes the high numbers rare as well.

    (2) Roll dN. The player can choose, once, to re-roll this result. The optimal strategy for minimized variance is to re-roll anything lower than N/2 (i.e., re-roll a 1 for d4, a 2 or 1 for d6, etc.). Roughly speaking, this inflates average hit points by N/8 while doubling the hit points of the bottom 15th percentile of characters.

  5. Tim

    November 15th, 2007

    My house rule is to give everyone max hit dice for their class. But of course all of the bad guys and monsters get maxed too ;)

  6. Hex

    November 23rd, 2007

    I agree the above method is no dice.

    We use the double rolling hit dice rule, however, if a roll is rerolled the player must keep the second result.

  7. Andrew

    December 4th, 2007

    If you’re worried about the fighter rolling low, but want to include some randomness, I would think the best way would be to subtract 2 from the max roll to gain +1 hp. ie. barbarian could do d12, or d10+1, or d8+2, d6+3, d4+4, or take 6. Minimum roll d4. Then add con bonus.

  8. Daniel

    January 12th, 2008

    One interesting one way to allow for a certain minimum hp is to have players who roll below average simply take the average. Thus, your players will always have at least the average. Of course, the most important is to take this into account when making enemies or challenges. As for max hp, it’s a risk, but can be worthwhile if done properly (I’ve seen close to this, with increased challenges, but we ended up retconing anyway).

  9. Contention

    January 13th, 2008

    The low roll is a problem, slightly offset by the fact that a normal fighter type should have at least a +2 con bonus (this varies, I know, but generally). The strategy we’re using at the moment is that you can either take (N/2)+1 for DN, or roll it and accept the result. This unfortunately discourages anyone with a low hit die from ever taking the chance, while leaving the character with high hit dice with a dilemma (being a former mathematician, I’d just take the (N/2)+1 even with a high hit die, assuming 20 levels).

    My personal choice would probably be some variant on Andrew’s suggestion: I’m not convinced that low hp characters are very viable, and I don’t think the game makes enough allowances for them.

  10. Jorunkun

    January 21st, 2008

    In levels one to three I think it’s a good idea to let PCs have above-average hitpoints. From a GM perspective, your choices for fun, appropriate challenges are severely limited if a character can be killed by just one unlucky blow.

    In my current campaign, I gave everybody max hitpoints at level one and let them keep the best of two rolls at level two. For every level up after this the rule is one optional re-roll, must keep second roll.

    I guess technically, monster hp should be rolled using similar rules for balance purposes … but then I hardly ever roll monster hp anyhow: They have average HPs, but get more or less on the fly, depending on how combat goes and what best serves to dramatise the story.

  11. Elkor

    January 21st, 2008

    In the 3.5 game I’m in (not running) we re-roll if the roll is under the midpoint.

    While this could be quantified mathematically as N/2 + dN/2, we just roll and figure it, then re-roll.

    We’re still early in the game, so the GM might change it later on.

    Though I like the N/2+1 for the Bard and Sorcerer (or other d4 classes).

  12. Glug

    January 23rd, 2008

    I’ve been using the roll twice method that my friend has been using for his game. This is also an example of house rules being contagious :) If I had to do it all again, I would give you the first half of your HP, and roll the other half. As in:
    d4 = 2+1d2 | d6 = 3+1d3 | d8 = 4+1d4 | d10 = 5+1d5 | d12 = 6+1d12

    This means that everyone has at least a hair above average hit points, and still some randomness. There’s obviously more randomness at the top end (barbarians with 7-12, wizards with 3-4), but I will never run a game where I’ll allow a barbarian to roll a 3 for hit points, period. It’s one thing to roll poorly in a critical situation, but it’s yet another to miss out on one of the prime features of your class due to a single die roll, and be stuck with those consequences for the rest of your life.

  13. Digo

    May 20th, 2008

    In the past few campaigns I’ve used this method:

    Maximum hit points for the first 3 levels, there after roll for hit points as normal but always reroll 1s.

    My tank players will usually be alright with an occasional 2 or 3 rolled and the mages always love it since they have HP closest to average with this method. For my group of 4 years this has worked fine. :)

    Of course as a DM I do have back up plans for those who tend to roll low consistently and fall behind the curve… finding an occasional “Potion of Perminant +1d6 HP” in a treasure trove is not a bad way to bump up those lagging scores. :)

  14. Professor Arhkham

    July 14th, 2008

    Here’s how we do it: :-)
    1st level characters get maximum hit points
    All rolls thereafter for hit points are straight rolled.
    The feat Toughness allows characters to re-roll 1′s (in addition to the normal description)

  15. KasraKhan

    July 19th, 2008

    1st level get max hit points, and level one adventures don’t involve combat. Pure roleplaying and skill checks, level to 2 before any combat. Level 1′s are too fragile.

    I generally judge each case separately. If a fighter has slightly below average hitpoints, but above average stats (strength, dex) I let it slide. Another option to burn a wish to reroll all hit die for a character, but again that could be good or bad.

    Bad rolls really only affect the high die type users – a 1 fora wizard doesn’t hurt like a 1 for a barbarian, so that must be taken into consideration.

    Also consider party makeup. If there are 2 clerics of 4 characters, let them keep the 1′s!

  16. Rekres

    October 7th, 2008

    The simplest fix…. Everybody gets the average hitpoints across the board. Solves the problem of the unlucky who keeps rolling low hitpoints and the inflated power of those who get too lucky.

    1d4 = 2.5
    1d6 = 3.5
    1d8 = 4.5
    1d10 = 5.5
    1d12 = 6.5

    3 possibilities: 1) Round down… 2) keep factionals, every other level equals an extra 1… 3) round up

    In my last 3.5 campaign, the PCs got max at first, and average with fractions for each level after.

  17. Tom Barta

    October 8th, 2008

    I’m DMing a campaign currently at level 3. So far, I’ve offered to let the players choose any number of dice to roll, and then they must average the results (rounding up to the nearest integer, so it’s slightly in their favor). They get to choose the level of risk they’re taking. At levels 1 and 2, they picked 2-4 dice to protect themselves from bad rolls, but by level 5 or so they’ll be back to standard HP rolls, to re-capture the fun of the risk.

  18. Matt

    November 7th, 2008

    Having played both sides of the spectrum, I’d prefer to have my characters roll for HP, and I’d prefer to give them every opportunity to roll well…

    I’ve taken averages, but that’s not fair to the players. A barbarian who has a d12 loses 5-6 hp per level. At the higher end of the spectrum, that’s an extra 100 potential hp, and at the lower end, that’s an extra hit from a longsword…

    Overpowered PCs can be compensated with by more and higher powered monsters. If the fear is that they’ll fail saving throws vs more powerful NPCs, but throw more bruisers at them.

    In the end, I’ve found it better for the party tanks to have the HP to suck up a lot of damage.

  19. John

    November 15th, 2008

    It’s interesting to note that 4e assigns maximum hit points at every level. Our approach in 3.5 has been to max the hit points for the first three levels. After that, players have a choice:

    Option 1 – Average Result
    They can choose the average number of hit points (even level equals half the die so D6 is 3 for levels 4, 6, 8 …; odd level equals half the die plus 1 so D6 is 4 for levels 5, 7, 9 …

    Option 2 – Straight Roll

    But the most important consideration is that all of this takes place within the larger framework of the complete game system translated into the campaign. We often have cleric-lite parties. Thus the need for various magic, summoning spells for hit point sponges, or allies (in the crawl or during rest). Encounters also get adjusted based on the nature of the party. So there is no

  20. John

    November 16th, 2008

    silver bullet of a rule mod as everything is connected. What’s more important is to seek balance.

    Clarification – each level after 3 the players choose Option 1 or 2; they get to make this decision each time.

  21. Matt

    December 15th, 2008

    I disagree. You seem to be implying that the game is perfectly balanced as written for every gaming style. That is impossible.
    For some styles of gaming double rolling, average hit points, and other hit point tweaks are perfectly reasonable.
    Of course it affects overall game balance and that must be taken into account. However, it does not outright break the game. It is just a matter of style of play.

  22. Quicksilver

    August 25th, 2009

    I have to agree with Matt. There’s no one answer to every situation. But i also have to point out that GM’s RARELY ever roll for the HP of their monsters, which means the monsters get average every fight, while the pc’s get their butts kicked or they over-survive every fight. If you make a rule for your pc’s, then make it apply to your monsters. If the pc’s are known to roll low, then the monsters should be known to do the same, except for special occasions. Keep it fair, most of all keep it fun.

  23. zox

    August 30th, 2009

    We play it like this: you can reroll if you want but you *have* to take the second roll even if it’s worse that the first one.

  24. Dan

    October 28th, 2009

    We tend to have high-powered characters anyway, taking on encounters with an ECL at least 1 or 2 levels higher than our party average level. As a result, we tend to overpower our characters – for example, rerolling 1s in ability score generation, or taking the average die roll on a hit die if you roll under half (or if you roll a 1). It doesn’t tend to unbalance things too much as long as the DM uses the same rules for his NPCs and monsters, or always throws average party level + 3 or so ECLs at us.

  25. Zach

    April 11th, 2010

    I think the whole argument about how having higher hit points makes the character more relaxed in combat is kinda loaded in one direction. Some times a player just flat out rolls high for his hit points. Is that bad for gameplay then when random good luck happens? We had Elmo join us for the original Temple of Elemental Evil and for the first 4 new levels he gained, the DM rolled 8s for HP (We always roll HP in front of the group) and my paladin often rolled 7-10 the majority of the time. That was good for us…

    Meanwhile my sister in law Amanda’s melee ranger was on the opposite spectrum. She had a +1 Con and rolled 1-3 the majority of the time. By the time we reached the pyramid with the earth elementals she was a 6th level (I think) ranger with 32 HP (on 7d8+7? ick!) She got hit by a critical and went from full health to -10 in one blow. She was careful and safe but her bad rolling completely screwed what was supposed to be a melee fighter.

    PCs are supposed to be a cut above the rest so I don’t see why extra HP should be condemned… no one wants to think their big bad melee character is as durable as an adobe house in a rain storm. Besides… if you are that concerned with the die going from a 5.5 to a 7.15… just take average life for a monster and bump it up the same increment or maybe a bit under.

  26. Rory

    November 29th, 2010

    I am currently running a Greyhawk Campaign using the Pathfinder set of rules.

    I like my player’s characters tough than the average Joe soap.

    Maximum hit points for the first 3 levels, then from level 4 onwards we use the sysytem below.

    d4 = 2 + 1d4/2
    d6 = 3 + 1d6/2
    d8 = 4 + 1d8/2
    d10 = 5 + 1d10/2
    d12 = 6 + 1d12/2

    I also tend to keep the gloves on for the first 3 levels so that the players can find themselves and at least let the character develope a bit. BUT level 4 the gloves come off!!

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