Damage per round formula help


Advice


Could someone post me the current DPR formula that's being used.

Also, could someone explain generally how to do the formula. I remember trying way back when, thought I had everything right, and ended up getting a very incorrect number.


mrofmist wrote:

Could someone post me the current DPR formula that's being used.

Also, could someone explain generally how to do the formula. I remember trying way back when, thought I had everything right, and ended up getting a very incorrect number.

There is an excel program that does all of the work for you. I never use the formula since the excel chart is easier to adjust.

PS:I flagged the other post since you made two. That way everything can be in this thread. I will try to find the link for the chart.


A Man In Black wrote:

The damage formula is h(d+s)+tchd.

h = Chance to hit, expressed as a percentage
d = Damage per hit. Average damage is assumed.
s = Precision damage per hit (or other damage that isn't multiplied on a crit). Average damage is again assumed.
t = Chance to roll a critical threat, expressed as a percentage.
c = Critical hit bonus damage. x2 = 1, x3 = 2, x4 = 3.

Posted in the DPR Olympics Thread


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The formula is hd+tchd. This can be expressed as hd(1+tc)
Another way to write it is h(d+s)+tchd.

h = Chance to hit, expressed as a percentage
d = Damage per hit. Average damage is assumed.
s = Precision damage per hit (or other damage that isn't multiplied on a crit). Average damage is again assumed.
t = Chance to roll a critical threat, expressed as a percentage.
c = Critical hit bonus damage. x2 = 1, x3 = 2, x4 = 3.

The link to the excel sheet is here

I have never worked it by hand, but when I use the excel sheet I am normally no more than .1 or .2 away from what other people get when they do it the hard way. It is no harder than any physics formulas I have done though so I am sure I could do it if I had too.


wraithstrike wrote:

The formula is hd+tchd. This can be expressed as hd(1+tc)

Another way to write it is h(d+s)+tchd.

h = Chance to hit, expressed as a percentage
d = Damage per hit. Average damage is assumed.
s = Precision damage per hit (or other damage that isn't multiplied on a crit). Average damage is again assumed.
t = Chance to roll a critical threat, expressed as a percentage.
c = Critical hit bonus damage. x2 = 1, x3 = 2, x4 = 3.

The link to the excel sheet is here

I have never worked it by hand, but when I use the excel sheet I am normally no more than .1 or .2 away from what other people get when they do it the hard way. It is no harder than any physics formulas I have done though so I am sure I could do it if I had too.

Awesome, thank you very much. It works perfectly.


hello. new to DPR calculations. but i like statistics. looking to learn to calculate my own builds by hand.

1st question:
as Chance To Hit (h) has two factors, strike bonus and AC score, what is a realistic way to calculate this %? is there a 20-level spread of expected AC values by CR that i can run my numbers against? what do most folks here use? why?
(tentatively, i am looking for levels 1, 5, 10, 15, 20, for simplicity)

2nd question:
how would i factor in multiple attacks? i would suspect that i just sum all the equation results for each individual attack. is this correct? also, how do i factor in multiple conditional attacks (think Cleave)? i would suspect that i would calculate the Cleave attack normally, then multiply that result by the first attack's 'h' value, before summing it. is this correct?

thanks in advance.


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rainzax wrote:

hello. new to DPR calculations. but i like statistics. looking to learn to calculate my own builds by hand.

1st question:
as Chance To Hit (h) has two factors, strike bonus and AC score, what is a realistic way to calculate this %? is there a 20-level spread of expected AC values by CR that i can run my numbers against? what do most folks here use? why?
(tentatively, i am looking for levels 1, 5, 10, 15, 20, for simplicity)

There's a Google doc floating out there somewhere, "Pathfinder Bestiary with Statistics" which breaks down things like mean and median AC for each CR level of monster. There's also the guide to monster creation" in the PRD, with a table of standard ACs by CR level.

Don't take an off by 1 error when you're calculating your hit chance. The number you need to _roll_ to hit is AC-Attack, multiplying that by 5% seems to give you your chance to miss. But mathematically that means you only miss if you roll a 1-6, you'll overestimate your miss chance by 5% if you just calculate from the roll directly:

Attack = +9
AC = 16

Need to roll 16-9 = 7
Probability of hitting = 100% - (7*5%) = 65% But, you only miss on a 1,2,3,4,5, or 6, which is actually 6*5%

So, probability of hitting = 100% - (AC-Attack-1*5%) (with bounds of 5% and 95%)

Quote:


2nd question:
how would i factor in multiple attacks? i would suspect that i just sum all the equation results for each individual attack. is this correct? also, how do i factor in multiple conditional attacks (think Cleave)? i would suspect that i would calculate the Cleave attack normally, then multiply that result by the first attack's 'h' value, before summing it. is this correct?

thanks in advance.

For multiple attacks, yeah just sum up the expected damage from each attack.

For cleave especially, it's a conditional probability that you can't really estimate: What's the probability that there will be another enemy adjacent to who you attacked and within your reach? If I add cleave into a DPR number, it's going to be misleading at best: It will over estimate my damage against a single target and underestimate my damage against multiple targets. I would just add a footnote along the lines of "A cleave attack is worth an expected x damage against a second enemy." Or maybe go so far as to say something like "A cleave attack gives me a y% chance of one shotting an equal CR mook."

Personally, I think the value of calculating DPR comes from estimating how long it will take you to kill a monster. If you start including numbers for things like cleave that don't actually contribute to killing an individual monster, you're getting away from planning and more towards epeening. But if you want to do that, you would calculate the cleave damage by multiplying expected damage of the cleave attack by the probability of your first attack hitting, much the same way crit damage is calculated. (You can't use cleave on iterative attacks, right? So you don't have to worry about calculating the probability of at least one attack hitting.)

Sczarni

Dotting.
Thanks everyone. This thread has been incredibly helpful.


Pathfinder Rulebook Subscriber

The excel sheet wraithstrike posted seems to be in the author's trashbin and will be unavailable soon.

Liberty's Edge

I copied it and shared it here. It isn't mine and I'm not trying to claim any form of ownership, simply hoping to make sure it sticks around another 2 years.


Pathfinder Rulebook Subscriber

Excellent, thanks! This is definitely useful for my calculations.

Sczarni

You know, I took one look at that excel sheet last night and decided that I had to figure out the math for myself in order to know if I was using the sheet correctly... Looking at the sheet again I still think it's harder to figure out than the math...

I'm specifically trying to figure out if it's advantageous or not to take UAS + Dragon Style + Dragon Ferocity on my PFS Natural Weapon Ranger Build who has 3 Primary Natural Attacks that do full STR mod to damage.

It's going to take me a while, but I think it will be a rewarding exercise.


Krodjin wrote:

You know, I took one look at that excel sheet last night and decided that I had to figure out the math for myself in order to know if I was using the sheet correctly... Looking at the sheet again I still think it's harder to figure out than the math...

I'm specifically trying to figure out if it's advantageous or not to take UAS + Dragon Style + Dragon Ferocity on my PFS Natural Weapon Ranger Build who has 3 Primary Natural Attacks that do full STR mod to damage.

It's going to take me a while, but I think it will be a rewarding exercise.

Sounds like an interesting build.

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