Bloodborne - AR Formula and Calculator

CALCULATING WEAPON ATTACK RATING (AR)
USE THIS DOCUMENT FOR THE NUMBERS ON ATTRIBUTE SCALING AND BASE DAMAGE FOR YOUR CALCULATIONS: https://docs.google.com/spreadsheets/d/1doP2HShMmJcHZFTNSZ3yVFxbUu4U1aO6yHIk9-wQ1Wo/edit#gid=811371374
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Base Damage + (Base Damage * Attribute Saturation * Attribute Scaling) * Gem% * Gem% * Gem% + Flat Damage

Note that Flat Damage is always added last, therefore it is not modified by any of the Gem%'s.
The Base Damage + (Base Damage * Attribute Saturation * Attribute Scaling) is added for every Attribute the weapon scales off of. For example, a weapon scaling off both Arcane and Strength will use an Attack Rating formula of:

Base Damage + (Base Damage * Strength Saturation * Strength Scaling) + (Base Damage * Arcane Saturation * Arcane Scaling) * Gem% * Gem% * Gem% + Flat Damage

As for calculating AR with certain attacks:
Base Damage + (Base Damage * Attribute Saturation * Attribute Scaling) * Gem% * Gem% * Gem% * Attack Modifier + Flat Damage = Attack Rating Before Enemy Defenses

Some weapons, such as the Blade of Mercy and the Burial Blade, scale off more than one attribute. To calculate their ARs, for example:

Physical Base Damage + (Physical Base Damage * Strength Scaling * Strength Attribute)
+ (Physical Base Damage * Skill Scaling * Skill Attribute)
+ Arcane Base Damage + (Arcane Base Damage * Arcane Scaling * Arcane Attribute)
* Gem % * Gem % * Gem % + Flat Damage

Physical Damage is both Strength and Skill.
Arcane Damage is Arcane.
Bloodtinge Damage is Bloodtinge.

Therefore, when the weapon uses more than one attack type, add another Base Damage + (Base Damage * Attribute Scaling * Attribute Saturation) to the math.

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TERMS

Flat Damage --> This is important. Flat Damage is NOT modified by anything, as you can see from the formulas above. Keep this in mind when you're thinking of using Flat Gems for your weapons.
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Base Damage --> The listed damage of the weapon before any bonuses and modifiers. Don't confuse it with the Attack Rating (AR) which you see upon pressing START.
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Saturation --> A number representing how much of a certain Attribute one has. At 99 STR, for example, one has 1.0(100%) saturation. 99 in a stat is the highest you can go, remember. Note that the scaling for the saturation is not linear, and it has two softcaps at 25 and 50, which is why many people choose not to invest over 50 in an Attribute. Here's some info:

Attribute Level 10 - 0.05 Saturation
Each additional point adds 0.03 in an Attribute before meeting the first softcap at 25.
Attribute Level 25 - 0.50 Saturation
Each additional point now adds 0.014 in an Attribute before meeting the second softcap at 50.
Attribute Level 50 - 0.85 Saturation
Each additional point now adds 0.00306 in an Attribute.
Attribute Level 99 - 1.00 Saturation
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Scaling --> The E-S Rankings actually function through numbers, wherein the letter grades are merely rough estimates. S scaling means a number over 1.0. For example, a +65 scaling gem is added onto the weapon's scaling as +0.65. See the document in the beginning for the specific numbers.
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Gem Percentage (%) - The percentage is represented as a decimal. A 27.2% gem, for example, becomes 1.272 for the formula. Note that gems multiply against other gems. EX: Three 27.2% is essentially a 205% gem. Gems may also have negative modifiers, like a -30% ATK DOWN curse.
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Attack Modifier - Every attack has a multiplier that determines damage. For example, charged R2's have a higher modifier than an uncharged R2. EX: A charged R2 might have a 1.8x modifier for more damage, etc. Flat Damage is not affected by the modifier, and is always added last. A 1.0x modifier is essentially AR x 1.0 = AR. Attacks may also have negative modifiers, like AR x 0.7.
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