D&D 5E Need help with incoming damage math

[Sword of Spirit]

I'm putting together some house rules, and in order to do so I need to make some estimates regarding average/typical incoming damage to characters at very high level (let's assume 17th+).

Specifically, I need to come up with an estimate of what percentage of their incoming damage is likely to be from attack rolls versus saving throws; as well as an estimate of what percentage is likely to be from B/P/S, versus all other damage types combined.

Has anyone put any math into this? If not, for those with experience, what are your gut impressions?

My arbitrary educated guess is damage is probably 60/40 attacks vs. saves, and 50/50 B/P/S vs other damage types.

If it matters to the math, assume I'm using the older versions of monster designs (for example, some monsters treat their attacks as magical weapons, and nothing that is conceptual B/P/S is replaced with another damage type).

 

[dave2008]

I'm putting together some house rules, and in order to do so I need to make some estimates regarding average/typical incoming damage to characters at very high level (let's assume 17th+).

Specifically, I need to come up with an estimate of what percentage of their incoming damage is likely to be from attack rolls versus saving throws; as well as an estimate of what percentage is likely to be from B/P/S, versus all other damage types combined.

Has anyone put any math into this? If not, for those with experience, what are your gut impressions?

My arbitrary educated guess is damage is probably 60/40 attacks vs. saves, and 50/50 B/P/S vs other damage types.

If it matters to the math, assume I'm using the older versions of monster designs (for example, some monsters treat their attacks as magical weapons, and nothing that is conceptual B/P/S is replaced with another damage type).

Current rules or future rules? The 2024 monsters (particularly at higher levels) are moving to use other types of damage than B/P/S. So at level 17+ I think you will find most damage is not B/P/S in 2024 and beyond. I would guess 80% (or more) is other. No idea on attacks vs saves.

 

[Stormonu]

Highly dependent on what monsters you're expecting to throw at the PCs. The CR design table might be able to give you some idea of the amount of expected incoming damage, but you'd have to look at the actual opponents that your planning to use to get an idea of what the damage form will be, then calculate from there.

Though the one thing the CR table doesn't factor in is the % chance that damage will actually land on a PC, based on the target's AC/saves. Though I think the expected attack bonus/save DC might be considered the "50% chance" of success and you can tweak expected output up or down based how the PCs average AC/saves deviate from the CR design table.

 

[Sword of Spirit]

Current rules or future rules? The 2024 monsters (particularly at higher levels) are moving to use other types of damage than B/P/S. So at level 17+ I think you will find most damage is not B/P/S in 2024 and beyond. I would guess 80% (or more) is other. No idea on attacks vs saves.

Current rules.

 

[Sword of Spirit]

Highly dependent on what monsters you're expecting to throw at the PCs. The CR design table might be able to give you some idea of the amount of expected incoming damage, but you'd have to look at the actual opponents that your planning to use to get an idea of what the damage form will be, then calculate from there.

Though the one thing the CR table doesn't factor in is the % chance that damage will actually land on a PC, based on the target's AC/saves. Though I think the expected attack bonus/save DC might be considered the "50% chance" of success and you can tweak expected output up or down based how the PCs average AC/saves deviate from the CR design table.

I'm thinking of a platonic ideal typical/average D&D mix of monsters. For these purposes I don't actually need to know hit chances or saves, just what percentage of damage aimed at them is coming from different sources.

 

[aco175]

I'm not quite understanding the question. If I am making an encounter or several to go against a high level party I think most of the attacks would come from weapons (swords, claws, bites, etc...). There might be a dragon with a bunch of piercing/slashing/bludgeoning (PSB) attacks. There would be encounters with liches and demons and such as well. These might have a group of monsters with casters and tanks going against the PCs. These encounters would likely be 80% PSB and 20% saves. There may also be encounters that are traps and environmental things like lava, forcing saves.

Overall I think/feel that in a high level dungeon the PCs can expect 75-80% regular attacks and 20-25% saves.

 

[Stormonu]

I dunno, at 17th+ level I sort of expect a lot of extraplanar (demons, devils, elemental, celestial) opponents or enemy spellcasters. I'd be surprised if a large percentage was B/P/S damage and not force or elemental/radiant of some sort. Also, I'd expect a lot higher percentage of saves (for half) vs. attacks against AC.

However, someone would have to go through the monsters to get an actual ratio instead of us just guessing. I think there was a thread on here where someone did that, but frankly I'm not inclined to go hunt it down.

 

[Clint_L]

I went to DnDBeyond and filtered monsters to only include levels 17+ and almost all of them have pretty hefty physical attacks. I'm actually not sure if the ratio is that different than at lower levels; instead, everything just hits harder, whether spell effects, physical attacks, or others, such as breath weapons.

The big difference I am noticing is that higher level creatures are much more likely to have powerful abilities that don't necessarily do damage but offer huge tactical advantages. I don't know how OP would account for that.

 

[Sword of Spirit]

Thanks for the thoughts!

I went to DnDBeyond and filtered monsters to only include levels 17+ and almost all of them have pretty hefty physical attacks. I'm actually not sure if the ratio is that different than at lower levels; instead, everything just hits harder, whether spell effects, physical attacks, or others, such as breath weapons.

The big difference I am noticing is that higher level creatures are much more likely to have powerful abilities that don't necessarily do damage but offer huge tactical advantages. I don't know how OP would account for that.

If the percentages don't change much, that's actually very helpful to know, because it means that damage is still mostly coming from attacks, and from B/P/S (though presumably a lower amount of B/P/S due to other damage types stacked on attacks at higher levels).

Other abilities won't impact what I'm doing. I'm basically trying to determine how a couple of things work out:
1) How much (percentage) damage is typically mitigated by an item that causes your attackers to have Disadvantage to hit you (like the cloak of invisibility which should normally allow you to remain invisible throughout all of a day's fights).
2) How much (percentage) damage is typically mitigated by an item that grants you resistance to B/P/S damage.

 

[Clint_L]

The value of disadvantage varies according to the roll needed to hit, but at high levels when monsters typically have very high "to hit" modifiers, it is probably worth around +3 AC. The amount of damage mitigated by resistance should be pretty easy to work out.