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An Essay by Justin Alexander

Hit points have been around for more than 30 years now. (Longer if you count their antecedents in wargaming.) So you might think that, by now, people would have a pretty firm grasp on how these mechanics worked, what they represented, and what it means to lose hit points.

You might think that. But you would be horribly mistaken.

Basically I'm writing this little mini-essay because I'm tired of engaging in the same painful debate every two months. I want to be able to simply point people to this essay and say, "Look, this is the way it works." (This won't actually have much effect with people who prefer to be mired in fallacies and foolishness, but it will at least delay the day on which I will inevitably succumb to a lethal case of carpal tunnel syndrome.)

So, first I'm going to repudiate the two primary fallacies which lead the innocent astray when it comes to understanding hit points. And then I'm going to pull my Big Reveal an explain the beautiful abstraction which lies at the heart of the hit point system.

(It should be noted that this essay specifically deals with the type of inflationary hit point system found in D&D. The term "hit points" may also be used for very different damage tracking systems, to which this essay probably won't apply at all.)



The first fallacy goes like this:

1. Dupre has 100 hp.

2. A goblin with an axe has hit him 10 times and done 78 points of damage.

3. Clearly, the goblin has hit Dupre in the face 10 times and Dupre is still alive! That's ridiculous!

The fallacy lies in the illogical leap from point 2 to point 3. A moment's consideration clearly reveals that there is absolutely no reason to assume that, every single time the goblin landed a solid blow, it meant that the goblin planted his axe straight between Dupre's eyes.

For example, imagine that you're talking to someone in real life and they said, "Did you know that Bill was actually shot three times during a mugging a few years back?" Given that Bill is still alive, would you immediately assume that, during the mugging, Bill was dropped to his knees, a gun held to his head execution-style, and the trigger pulled three times?

Of course not. You would assume that Bill was probably hit in the legs or the arms. If he was hit in the chest, you'd assume that he only survived because he got prompt medical attention. And if one of the bullets actually did take him in the head, you'd know that it was a medical miracle that he was still alive.

Similarly, there's no reason to assume that Dupre was hit in the face ten times with an axe. In fact, quite the opposite is true: There is every reason to assume that he wasn't hit in the face ten times with an axe.



The second fallacy is most often committed because, after escaping the trap of the first fallacy, people go to the other extreme:

1. Dupre could not have been hit 10 times in the face with axe and survived.

2. Therefore, Dupre was never hit with the axe.

3. Dupre won't be hit by the axe until a blow causes his hit points to drop below 0. When that happens, the goblin will have finally hit him with the axe.

The fallacy here lies in the leap from point 1 to point 2.

Let's go back to the example of Bill's mugging. If you friend said to you, "Did you know that Bill was actually shot three times during a mugging a few years back?" Would you assume that he meant, "The guy mugging bill shot his gun three times, but never actually hit Bill."?

Of course not.

In terms of D&D, the nature of this fallacy is more explicitly revealed when you look at something like poison. If the orc's axe is coated with poison and we embrace this fallacy, then Dupre has been exposed to the poison 10 times despite the fact he's never actually been hit by the axe.

And you can reproach this fallacy from multiple directions: If the hit point loss from blows that don't "really" hit is because Dupre is wearing himself out from dodging, why is dodging a +1 flaming sword more exhausting then dodging a +1 sword?

And, of course, you also have the oddity that, apparently, dodging a blow from a sword can be even more deadly to you than being hit by the sword.


The trick to understanding the hit point system is understand that a hit point is not equal to a hit point. In D&D, 1 hit point of damage always represents a physical wound. However, the severity of the wound represented varies depending on how many hit points the victim has.

For a character with 1 hp, that 1 hp of damage represents a serious wound -- a punctured lung, a broken leg, or something of that ilk.

For a character with 10 hp, that 1 hp of damage represents a meaningful wound -- a deep but or a broken rib.

For a character with 100 hp, that 1 hp of damage represents an essentially inconsequential wound -- a scratch, a bruise, or the like.

The reason any particular character has fewer of more hit points (and, thus, varying the severity of any given wound they receive) is abstracted. For some characters its skill; others luck; others physical toughness; others divine grace; others magical protection; and so forth. For most PCs, it's some combination of all these things.

This is a beautiful abstraction because it allows for quick, simple, and entertaining gameplay. One could certainly design a system with variances in skill, luck, toughness, divine favor, magical protection, and the like were all separately modeled. Many such systems exist. But none of them are as simple, easy, or fun or as hit points have proven to be.


No. The system is an abstraction, and that brings with it both advantages and disadvantages. The advantages are simplicity and completeness. The disadvantage is that you can't reliably pull concrete information back out of the abstraction -- and, if you try, you'll eventually find corner cases where seeming absurdities crop up.

For example, it's theoretically possible for a sufficiently weak character to deal no more than 1 hp of damage per attack. Such a character could, theoretically, land 100 blows on a character with 100 hp before taking him down. Add poison to the scenario, and you've now locked yourself down to a scenario where the weak character is, apparently, whittling his opponent to death.

Such corner cases are statistical oddities, but they're going to reliably crop up in any system which doesn't require several additional orders of complexity.

Which leaves the only significant and intractable problem with the hit point abstraction: The cure spells. Despite the fact that the number of hit points required to represent a wound with a particular severity varies depending on the character's total hit points, a cure spell heals a flat number of hit points. Thus, a cure light wounds spell used on a 1st level fighter will heal grievous wounds. When the same spell is used on a 10th level fighter, on the other hand, it can't handle more than a scratch.

This is a legacy issue which has been retained for reasons of game balance. But if you want to fix this, simply have cure spells work more like natural healing: Multiply the number of hit points cured by the creature's HD.

Hit points aren't a one-size-fits-all solution to tracking wounds in roleplaying games. There are lots of reasons why you might want a more concrete representation of actual wounds or a realistic modeling of incapacitation.

But hit points are often attacked for the most erroneous of reasons. And, as I said up front, I don't necessarily expect this little essay to make any sort of huge dent in that tidal wave of ignorance and faulty logic. But it might help me keep my blood pressure down.

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