Inspired by this, this, and this, I just processed this list of monsters to get the average (and standard deviation) AC in monsters, by CR. It comprises all the SRD monsters, I believe.

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A common DPR chart shows the average DPR of a character at a given level. DPR often depends on the to-hit bonus of characters and the AC of monsters. For example, at level 10, Bob can either:

  • increase his damage bonus by +2
  • increase his to-hit bonus by +2

We can't justify which one is better without knowing how often Bob hits his attacks against his enemies.

Can this graph be used in DPR charts? Ideally, it could be translated to find, for a character of a given level, the average AC of the monsters he faces.

One way would be to consider the character's level to match the CR of enemies. So, for example, Bob would calculate its accuracy against an enemy of CR10. Bob has a +5 to hit, does 9 damage per attack, 3 attacks per round, and a CR10 monster has an average of 18 AC.

  • With +2 damage, Bob has 40% hit chance, 11 damage per attack, and 13.2 DPR.
  • With +2 to-hit, Bob has 50% hit chance, 9 damage per attack, and 13.5 DPR.

If a MonsterCR to CharacterLevel matching isn't adequate, what would be? Can we use standard encounter-creation rules to build a chart that matches player level to average enemy AC?

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    \$\begingroup\$ What's your question exactly? The chart is a tool that can assist with encounter creation, but the body of your post seems to ask a different question about metrics that can be used to balance encounters. \$\endgroup\$
    – JRodge01
    Nov 15, 2019 at 14:19
  • \$\begingroup\$ @JRodge01 I don't ask about encounter balancing. I ask how to obtain the average enemy AC for each character level, and if this graph (showing AC by CR) is adequate. I've reworded the question to make it clearer \$\endgroup\$
    – BlueMoon93
    Nov 15, 2019 at 14:28
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    \$\begingroup\$ How are the mean and standard deviation supposed to be applicable? There isn't a known probability of encountering each monster. \$\endgroup\$
    – Mark Wells
    Nov 15, 2019 at 15:00
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    \$\begingroup\$ Statistically, that's no more valid than assuming any other distribution, such as "all monsters are hobgoblins". \$\endgroup\$
    – Mark Wells
    Nov 15, 2019 at 15:17

1 Answer 1



As players level up, the difficulty of encounters increases, in general. However, that difficulty can be ramped up by including higher CR enemies, by including more enemies, or both.

Your chart would be helpful if only enemy CR increased. However, since a DM or adventure designer could simply include more enemies, that would throw off any simple relationship between character DPR and monster AC.

  • \$\begingroup\$ So you would agree that it is not possible? Even if XP and encounter building rules, etc, were used? \$\endgroup\$
    – BlueMoon93
    Nov 15, 2019 at 14:53
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    \$\begingroup\$ This is the correct answer. You can't link "this is a CR15 encounter" with any meaningful AC value. It's possible to reach a CR15 encounter with nothing but CR2 AC11 Ogres with the encounter building rules. It's quite a few ogres, but it's a valid encounter, and nothing in it has more than 11AC. \$\endgroup\$
    – Theik
    Nov 15, 2019 at 14:57
  • \$\begingroup\$ Ok, it makes sense. Too bad, I was hoping there was some standard way of matching enemy CR to player level. +1 \$\endgroup\$
    – BlueMoon93
    Nov 15, 2019 at 14:59

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