Checking CR calculation for homebrew larger version of Giant Ape

Question

I am considering allowing a larger version of a Giant Ape, in which some of the stats have been embiggened to achieve the low end of CR8.

I would appreciate a confirmation that I am calculating this correctly.

In particular, it appears that what the DMG calls Damage Per Round, what is actually being assessed is average damage per round, assuming that the maximum number of most damaging attacks hit.

CR7 Giant Ape
AC12, 157hp (15d12+60), At. 2 @ +9 to hit, 3d10+6 dmg, DPR 45

CR8 Proposed Giant Ape [all other stats as RAW Giant Ape]
AC13, 168hp (16d12+64), At. 2 @ +9 to hit, 3d12+6 dmg, DPR 51

CR7 Giant Ape Calculation
Hp 146-160 = CR6, AC is more than two below 15, adjust DCR -1 to 5
DPR 45-50 = CR7, to hit is more than two above +6, adjust OCR +1 to 8
Average CR 6.5, round to CR7

CR8 Proposed Giant Ape Calculation
Hp 161-175 = CR7, AC is two below 15, adjust DCR -1 to 6
DPR 51-56 = CR8, to hit is more than two above +6, adjust OCR +1 to 9
Average CR 7.5, round to CR8

Given the negative response to this question so far, have I misunderstood the purpose of the cr-calculation tag? — Kirt, Nov 28 '20 at 07:26
Your related questions, linked for others' benefit: Are there any official CR 8 beasts that are not dinosaurs, for the purpose of the Polymorph spell?, Embiggening monster for higher CR for Polymorph (Homebrew) — V2Blast, Nov 28 '20 at 07:43
So the question is whether your calculation is in line with the DMG values? That's not difficult to check, I'm just ascertaining whether that's what you're looking for. — Anagkai, Nov 28 '20 at 10:06
@Anagkai Yes. One question is whether I cam doing the calculations correctly, which I think is straightforward. The other is whether I am using the correct values. For example, the passage in the DMG says "read down the Damage / Round Column", but AFAICT, never defines how one obtains the value for DPR of a monster. — Kirt, Nov 28 '20 at 15:14

score 2 · Accepted Answer · answered Nov 28 '20 at 15:32

The calculation looks correct

I do not see any problems, neither logical nor mathematical nor from misusing the table.

The damage calculation is explained under the step Damage

It seems your confusion about how the DPR is calculated comes from the fact that you just read STEP 4: FINAL CHALLENGE RATING (DMG p. 274-275) which explains how to translate a damage value to a CR. The determination of the damage value is performed like you assume which is explained on DMG p. 278 in the part named STEP 11: DAMAGE which says under Overall Damage Output (emphasis mine):

To determine a monster's overall damage output, take the average damage it deals with each of its attacks in a round and add them together. If a monster has different attack options, use the monster's most effective attacks to determine its damage output.

So "average damage" means average damage assuming it hits? That is, it is not pro-rated for the attack bonus? — Kirt, Nov 28 '20 at 17:06
@Kirt Yes. Variation based on to-hit chance would be factored into the To Hit column of the CR table and the associated correction. — BBeast, Nov 29 '20 at 06:06

Checking CR calculation for homebrew larger version of Giant Ape

1 Answers1

The calculation looks correct

The damage calculation is explained under the step Damage

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