Bloodborne Attribute Scaling Calculation

Bloodborne Attribute Scaling Calculation by Silvard

Hello guys, first of all let me say that this is building upon Skorbrand’s and RealBazou’s observations, as well as the data provided by those who have posted their maxed weapons with their stats (although I need more of those, I’ll explain down below). So with my own observation and testing, supplemented by these resources, I’ve worked out the individual scaling on most of the stats on each of the Trick Weapons and Firearms and made a calculator with the goal of predicting your base attack rating (without any gems) with any +10 weapon and any given build within a +-1 ATK margin of error.

If you’re interested in the calculator then you can find it here:

Please bear in mind that I’m not a graphic/UX designer, so aesthetically it’s a work in progress. It also focuses on offensive stats (without taking into account blood gems due to their inconsistent nature, more on that later), if there’s a demand for defense or rune calculation I will add it, but armor is far less important in this game compared to other Soulslike games. Any feedback, comments or suggestions are more than welcome.

Now on to the meaty math. If you’re a Souls veteran then some of this stuff will seem familiar to you.


The formula for unmodified attack rating is the same as in past games and is as follows:

Attack Rating = Base Damage + (Base Damage * Attribute Scaling Ratio * Attribute Rating)

Since every Trick Weapon in this game scales with at least 2 attributes, we’d need to add the + (Base Damage * Attribute Scaling Ratio * Attribute Rating) part of the formula for every attribute the weapon scales with, and the elemental base damage plus the relevant attribute in the case of hybrids, such as:

Tonitrus Unmodified ATK Rating = 160 Base Phys. Damage + ( 160 * Strength Scaling Ratio * Attribute Rating) + (160 * Skill Scaling Ratio * Attribute Rating) + 60 Base Bolt Damage + (60 * Arcane Scaling Ratio * Attribute Rating)

Now let’s break down the formula:

  • Unmodified Attack Rating: This is the WPN ATK stat you see you on your status screen. It does not equate to the damage you do with a weapon, since that is affected by defenses and damage type, but there’s always a correlation. The unmodified part means that this is without blood gems. Blood gems are inconsistent in their returns, according to my testing, which makes it impossible for me to calculate their effect while sticking to a tight margin of error. I believe there’s either a hidden ratio/scaling stat behind them depending on the weapon (for instance a gemmed out Holy Blade has, in my testing, slightly less damage than the gem values and simple math would otherwise indicate, while a Stake Driver has slightly more) or the variance is due to From’s weird rounding/truncating rules. We can calculate the blood gems’ effect on this attack rating as an optional final step, more on that further below.
  • Base Damage: Pretty self explanatory. It’s the base damage of the weapon of any given damage type.
  • Attribute Scaling Ratio: It’s ratio that is specific to an attribute and a weapon, and its value determines how well that weapon scales with that attribute. This is represented in game with a letter, going from S=>A=>B=>C=>D=>E=>-, where S is the best scaling and – is no scaling at all. As RealBazou pointed out, this letters are ranges as opposed to exact values, which renders them a bit useless for using a numeric formula. These values, however, can solved from the information we have at hand, and we will do so in a bit.
  • Attribute Rating: This number determines what percentage of its scaling potential an attribute contributes to the bonus damage of a weapon. It’s weapon independent and it scales the same regardless of attribute (Vitality and Endurance notwithstanding); it only varies depending on the number of total points you have in an attribute. This is what determines the diminishing returns behind attributes. It’s one of the major points of difference between Bloodborne and past Souls games, and the ramifications upon the meta game still remain to be seen.

Attribute Rating

While RealBazou’s results regarding this number are not wrong, we have to refine them a bit further in order to get more accurate numbers. Luckily with Skorbrand’s data and more individual testing I’ve been able to do just that.

Attribute Threshold Percentage of Potential Scaling
10 5%
25 50%
50 85%
99 100%

The growth of Attribute Rating is linear within these thresholds, which means that increasing from 5=>6 gives you the same percentage increase as 6=>7, or 14=>15 is the same as 20=>21. The variance you see in your level up screen is due to From’s rounding/truncating, and stats catching up. It also means that attribute increases between 25 and 50 are worth roughly half of what an increase between 10 and 25 is worth. For specific numbers please refer to this table

Either way, with this value we can determine the Attribute Scaling Ratios, and we will do so up ahead.

Attribute Scaling Ratios

So, how we do determine these? Well, we need data points to extrapolate them. Luckily there were some +10 Weapons pictures with their stats (and respective attributes) posted on reddit, and for comparison…well, it was a painstaking process of backing up my save, upgrading weapons, and restoring… Anyway, thanks to those, I had at least 2 data points for most weapons, and had every variable except for the scaling ratio…but that’s a simple system of linear equations. Solving that gave me these preliminary ratios, with which we can get ATK ratings using the above formula, at least for the vast majority of physical and hybrid attack weapons.

Weapon Strength Ratio Skill Ratio Bloodtinge Ratio Arcane Ratio
Beast Claw 0.62 0.335 0.52
Blade of Mercy 1.085 0.69
Burial Blade 0.3 0.75 0.69
Chikage 0.25 0.65 1.1
Hunter Axe 0.65 0.35 0.55
Kirkhammer 1 0.29 0.695
Logarius’ Wheel 1.1 0.56
Ludwig’s Holy Blade 0.8 0.8 0.88
Reiterpallasch 0.2 1 0.4
Rifle Spear 0.3 0.7 0.65
Saw Cleaver 0.6 0.4 0.55
Saw Spear 0.5 0.63 0.625
Stake Driver 0.6 0.55 0.625
Threaded Cane 0.29 0.9 0.65
Tonitrus 0.65 0.25 0.5

And for the firearms and gadgets:

Weapon Bloodtinge Ratio Arcane Ratio
Cannon 0.4
Evelyn 1.35
Flamesprayer 0.7
Hunter Blunderbuss 1
Hunter Pistol 0.85
Hunter’s Torch 0.6
Ludwig’s Rifle 0.5
Repeating Pistol 0.8
Rosmarinus 1.21

Now, we have what we need to figure out what your attack will be, you simply substitute the respective values as such:

What’s my Holy Blade +10’s unmodified attack at 30 Strength and 25 skill?Unmodified ATK = 200 + (200 * 0.8 * 0.57) + (200 * 0.8 * 0.5)
Unmodified ATK = 200 + (91.2) + (80)
Unmodified ATK = 200 + 171.2 = 371 (after rounding down/truncating)

Blood Gems

Optionally, after determining your Unmodified ATK rating, you can calculate the effects of adding gems to your weapon. We’ll focus on stacking same damage type gems (with ATK UP functioning as a wild card), why? Because gems stack multiplicatively, not additively, if they’re of the same type of damage. This means stacking same damage type gems of as high a value as you can find is the most optimal way to maximize your damage.

So what if I add to my 371 ATK Holy Blade, a 18% Phys. ATK Up gem, a 7.3% ATK Up gem, and a 10.5% Phys. ATK Up gem? Let’s see the formula:

Gemmed ATK = Unmodified ATK * (1+Gem 1) * (1+Gem 2) * (1+Gem 3)
Substituting, keeping in mind that percentages are expressed as decimals
Gemmed ATK = 371 * 1.18 * 1.073 * 1.105
Gemmed ATK = 519 (rounded down/truncated)

And that’s how you do it! Or simply use the calculator below, which will do all of it for you:

Hopefully this will help you guys figure out builds and stat breaks and distributions.

How you can help complete this guide/calculator and make it better!

  1. Missing Scaling Ratios: As you can see in the table up above many weapons are missing their Arcane ratios and 2 weapons in particular are missing all of them! The reason for the former is that my primary character, the one with the materials to upgrade and test, has a pitiful amount of Arcane. This makes it impossible to determine an accurate ratio. If you have any of these weapons at +10 or +9 (you can check how it will look like at +10 on the fortify menu) and you have a decent amount of Arcane, please add the single lowest value gem you have which converts its damage to elemental and post a picture of its stats here, remembering to state the value of the gem. The reason for the latter is, well, I don’t have a Beast Claw or a Burial Blade yet! If you have any of these at +10 please post a picture of their stats and your attributes here.
  2. The Effect of Gems: Gems are supposed to stack additively and multiply your ATK, please check your gems and weapons and record any discrepancy between its expected value of ATK*(Gem1+Gem2+Gem3)/100 and the actual value on your status screen. Stick to the same damage type to reduce noise. Testing confirms that gems stack multiplicatively, not additively, which was throwing off my expectations. This means that gems are even more powerful than I initially thought.
  3. Feedback: Have any doubts about anything? Unclear on something? Caught a mistake? Need something else to be added to be calculated at the moment of deciding a build? Go ahead and say it!

Update 1: Added the scaling ratios for the Burial Blade, thanks toalexp1128 and jamalabd. Added the arcane scaling ratios for the Beast Claw, Ludwig’s Holy Blade, Kirkhammer, and Hunter Axe, thanks again toalexp1128. Adjusted the scaling of Evelyn based on further testing (1.33 => 1.35). Figured out what was throwing me off with the blood gems (I can’t believe it) and have since added their section of the guide and calculator, although the results are only accurate for damage types which stack and affect the entire weapon. Since that’s the optimal situation anyway, it’s what you want to do.

Update 2: The table is complete! All preliminary ratios are accounted for, all that is left is for people to use them and report any discrepancies. A thousand thanks to alexp11288, jamalabd and MDK2k for being instrumental in the completion of the table/calculator. The calculator now also highlights which origin you should pick to reach your target attributes at the lowest level possible. As always, any doubts, suggestions or comments are welcome.

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