Hey!
I’ve seen an increasing amount of talk about the damage formula on the Genshin Impact subreddit, and I thought I would contribute what I can to the discussion.
I found that comprehensive information on damage calculations like the ones provided by u/robin were actually quite few and far between for onlyEnglish speakers like me.
My aim with this guide is to help you guys understand the principles of damage calculations to help you pick optimal gear for your characters.
There is a video summary of this here. I will timestamp each heading with the appropriate section of the video.
A lot of information is based on testing from the closed beta as well as translations from Chinese players. I’m not claiming to know everything about how damage works in this game! As far as I know, the damage calculations we’ll be using in this video are likely accurate, but keep in mind that they are unverified.
So with that in mind, I’ll try to keep it short and sweet (with pictures!), but if you’re not into numbers and don’t care for the game science, feel free to skip to the tl;dr.
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Well first, a quick google search led me to finding two formulae, which were reportedly sourced from Chinese CBT3 players and then translated and posted on the English mihoyo forum by user Blasterion.
https://forums.mihoyo.com/genshin/article/13629
https://forums.mihoyo.com/genshin/article/14696
The first formula is the defence formula, a calculation based on ATK power. Let’s have a look at them.
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This formula relates the total damage done to a target based on 3 things:

The target’s defence

The attacking unit’s level, and;

The attacking unit’s ATK power
e here represents Euler’s number, which is a mathematical constant.
The defence formula calculates damage done accounting for these three factors. The formula itself isn’t exactly easy to interpret, so I hopped onto to the internet again and threw it into a graphing calculator.
I substituted an arbitrary unit ATK power of 1000 for the purpose of making it a readable graph, and a character level of 80.
This is the first graph I produced. On the Yaxis is the total damage done. On the xaxis is the target’s defence.
What this means is that as the target’s defence increases, we get a decrease in total damage that follows this curve. If you’ve played video games before, that probably makes sense to you!
But that’s not all – what if we substituted arbitrary values and graphed how unit level affects total damage?
Well, it would look something like this:
Again I’ve included a unit ATK power of 1000 for consistency (though the graph isn’t quite as readable here because of the scale), and put an arbitrary value of 1000 for the target defence this time. Once again total damage is on the yaxis, and this time the xaxis represents your character’s level.
As you can see, your character’s level has a significant impact on the amount of damage done!
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OK, so now we know how those first two factors affect your total damage output… but we haven’t talked about ATK power.
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According to the formula I could find, it’s:
ATK Power = [(Character Base ATK + Weapon Base ATK) × (Weapon “Base ATK%” bonuses + Artifact “Base ATK%” bonuses)] + Artifact “ATK” flat bonuses+ Plume of Death artifact ATK
Great, this formula’s a lot more readable so I might explain this one without graphing it.
Your ATK power is based on a multitude of things, but as expected, flat ATK bonuses only add to your final ATK power.
What’s most interesting here is how your %ATK from your weapon and your artifacts interact with your character’s base ATK and weapon ATK. Notice how they add together before they multiply by each other?
The key point here is that you have less control over your character’s base ATK and the weapon base ATK, because you’ll probably be trying to max these things regardless (and there won’t be an opportunity cost). You do have control over the artifact total base ATK%, however, and it can make a big difference.
The point I’m trying to make is – if you are stacking ATK% on all your artifacts, you’re getting “diminishing returns” because they actually add together instead of multiplying together.
Simplified Example
I have 100 ATK total and I gain 30% base ATK from one artifact (1.3x) – now my total ATK is 130. Great! But if I add a second artifact that also has 30% base ATK*, I will add 30% base ATK to make it an* increase of 60% (1 + 30% + 30% = 1.6x), so now I have 100 x 1.6 = 160%. Cool!
Doesn’t sound like a bad increase in ATK power right? if you use one 30% ATK artifact and combine it with a 30% elemental/physical dmg artifact you would achieve 100 x 1.3 x 1.3 = 169%.
If looked at the formula carefully, you might have noticed that the formula appears to be missing %elemental damage or %physical damage… so I tested it (4:56).
If you look at the comparison, you can see that the %physical goblet build does just over 22% more damage on the strongest shot than the %ATK goblet build!
(The other smaller numbers you are seeing are noncrits from the bow, Oz’s extra damage, and the viridescent hunt bow whirlwind passive damage.)
This suggests that %physical and elemental damage are actually separate multipliers in your character’s ATK power, and that maybe the formula looks a bit more like this:
ATK Power = {[(Character Base ATK + Weapon Base ATK) × (Weapon “Base ATK%” bonuses + Artifact “Base ATK%” bonuses)] + Artifact “ATK” flat bonuses+ Plume of Death artifact ATK} × (“%Elemental/Phys” bonuses)
Keep in mind that only certain slots can roll certain %dmg bonuses, and this will also depend on whether you’re focusing on a physical or elemental build.
I have also not accounted for other damage bonuses, such as those from sets that increase “normal attack damage” – but it would seem this is additive with %ele/phys dmg bonus, rather than multiplicative.
Also note that I haven’t talked about elemental mastery and elemental reactions, which is a whole other can of worms that I don’t really want to open in this discussion.
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Optimal damage output for a single unit, not including elemental reactions, appears to be achieved with a combination of %ATK and %elemental/physical dmg on artifacts, rather than building all into %ATK. You achieve “diminishing returns” from stacking %ATK due to its additive, rather than multiplicative nature in the damage formula.
So what might that look like when you’re building your character?
A good starting point for building your carry character to maximise its damage output would be to have one %ATK artifact, one %elemental/physical artifact and your hat with %crit rate (or %crit dmg depending on where your stats lie here).
That about does it. Congratulations if you made it all the way through (it’s a bit heavy, I know)! Hopefully your brain has expanded slightly, or at least I’ve contributed to some good discussion.
bear_tek