Guidance – Theorycrafting 101: Measuring PC Damage

Welcome to Guidance, Private Sanctuary’s source for tips and techniques for the Pathfinder Roleplaying Game, written by Everyman Gamer Alexander Augunas. Today, we’re going to be talking about the difference between theoretical damage and practical damage in the Pathfinder Roleplaying Game.

I apologize in advance: this article is going to be a quick one because it is setting up for my Mythcleaving two-part series on rogues. But before we can get to that, we need to talk about how to measure a character’s damage because frankly, the Paizo community does it wrong. Often.

Why Measure Damage?

As I’ve mentioned, combat is the heart of the Pathfinder Roleplaying Game, so people often feel the need to compare the damage-dealing capacity of classes. It’s a logical thing to look at when comparing classes, especially martial types that often have very few alternatives in their tool kit. You’ll see some people take damage-dealing potential and use it to rank the classes; I personally don’t believe in this because most ranking systems I’ve seen only take theoretical potential into account and not practical potential. Example: paladins and cavaliers have a crazy-potent damaging ability in smite evil / challenge which drastically affects the amount of damage they can deal in a single round. The problem? The number of times the character can use of this ability is severely limited, so while the class has a theoretically high maximum damage potential, in practice the class’s damage dealing potential is much lower because most players will not be able to use smite evil in every combat they participate in. We won’t be discussing how to track damage over the course of an adventuring day in this article, but it is a factor to keep in mind when comparing damage outputs.

Ways to Measure Damage

It is important to know a class’s theoretical potential for damage as well as a class’s practical potential. I’ll briefly outline how to calculate both theoretical damage and practical damage below:

Theoretical Damage

Theoretical damage is easy to calculate because you are assuming that every attack you make hits. Here are the steps to calculating theoretical damage.

  • Step One: Determine the average damage of all variable elements of your attack. For example, weapon damage is a variable element: if my dagger damage is 1d4, I can deal 1, 2, 3, or 4 points of damage with my dagger when I attack. The average is equal to the average of all results on the die: 1 + 2 + 3 + 4 = 10. 10 / 4 = 2.5 average damage. If your attack has multiple elements of the same type, multiply them together. For example, a greatsword’s average damage is 7 (2d6 = 3.5 average damage per d6 * 2). RULE: A die’s average result is equal to half the number of sides the die possesses + 0.5. For example, half of 8 is 4, plus .5 equals an average result of 4.5.
  • Step Two: Add all numerical bonuses to damage that your attack possesses to your average variable result. For example, Power Attack’s damage bonus is a numerical bonus; it is a static value that does not vary. (Increase over the course of the game, yes, but the number it provides is not random.)
  • Step Three: The sum of your attack’s variable damage and numeric damage is your theoretical damage. Huzzah!

Practical Damage

Practical damage, on the other hand, is more difficult to calculate because it requires more statistics. Here are the steps to calculating practical damage.

  • Step One: Determine the character’s attack bonus. This includes all bonuses and penalties that you can expect the character to possess. For example, I usually allow the paladin to have his smite evil bonus, but I also allow all characters to be flanking. Don’t forget to calculate penalties such as Power Attack and Two-Weapon Fighting.
  • Step Two: Determine the character’s average damage per attack; this is identical to determining the character’s theoretical damage (see above).
  • Step Three: Determine the character’s AC benchmark. This is the AC that the character(s) participating in the comparison must be able to hit. I use the AC associated with a monster whose Challenge Rating (CR) equals the character’s level, drawn from Table 1-1: Monster Statistics by CR in Pathfinder Roleplaying Game: Bestiary for my benchmark ACs.
  • Step Four: Determine the character’s total attack bonuses for each of the twenty results possible on the character’s attack roll. For example, a character with an attack bonus of +5 would have a +6 if she rolled a 1, a +7 if she rolled a 2, a +8 if she rolled a 3, and so on. Do this with every result from 1 to 20 and note which attacks successfully hit the target AC. Remember that a 1 is always a failure (barring mythic rules) and a 20 is always a hit.
  • Step Five: Determine the weapon’s critical threat range and any bonuses the character possesses when confirming critical hits. For each critical hit, use the following formula to determine the critical hit’s damage: ((F*DPA)+S*(DPA*M))/20. In this formula, DPA is the weapon’s average damage per attack (aka its Theoretical Damage), F equals the chance that the critical hit will not confirm, S equals the chance that the critical hit will confirm, and M equals the critical damage multiplier. Do not uses percentages for F and S; use the number of results out of 20 that will confirm the critical hit. For example, if I confirm a critical hit against my target on a 12 or better, that means 11 results out of 20 will not confirm the critical hit (F) while 9 results out of 20 will confirm it. As with attack rolls, a 1 always fails to confirm the critical hit while a 20 always succeeds.
  • Step Six: Average all 20 damage results together. The result is your build’s practical damage. Remember that a miss deals 0 damage. (Unless a miss does deal damage, such as with the grazing shot deed.)

Why Bother With Practical Damage?

Some of you might be wondering why you should bother calculating practical damage instead of doing things the good, old fashioned way with theoretical damage. The major reason is that practical damage accounts for the benefits associated with a successful hit. So many theorycrafters calculate their build’s damage with the assumption that they hit, but as we’ll see with the rogue next week a poor attack bonus really hurts a character’s practical damage in-play because a character who does not hit deals no damage. This is a credence that any MMO player is familiar with, and it’s high time that this concept was applied to the Pathfinder Roleplaying Game.

And that about wraps up my thoughts on calculating average damage. What do you think? How do you calculate your character’s average damage? Does the difference between theoretical and practical damage matter to you? Do you care about the concept of Damage Per Round at all? Leave your answers and comments below, and I’ll see you next week with the  with a two-week special on rogues! Don’t miss it!

Alexander “Alex” Augunas has been playing roleplaying games since 2007, which isn’t nearly as long as 90% of his colleagues. Alexander is an active freelancer for the Pathfinder Roleplaying Game and is best known as the author of the Pact Magic Unbound series by Radiance House. Alex is the owner of Everyman Gaming, LLC and is often stylized as the Everyman Gamer in honor of Guidance’s original home. Alex’s favorite color is blue, his favorite Pathfinder Race/Class combination is kitsune ranger, and his favorite pastime is wearing the label “Mathematics Hipster” with pride!

Alex Augunas

Alexander "Alex" Augunas is an author and behavioral health worker living outside of Philadelphia in the United States. He has contributed to gaming products published by Paizo, Inc, Kobold Press, Legendary Games, Raging Swan Press, Rogue Genius Games, and Steve Jackson Games, as well as the owner and publisher of Everybody Games (formerly Everyman Gaming). At the Know Direction Network, he is the author of Guidance and a co-host on Know Direction: Beyond. You can see Alex's exploits at, or support him personally on Patreon at

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