Parameter Bonus

The Parameter Bonus rating, also known as Scaling, indicates the level of bonus damage one can do with a weapon, based on the associated stats. This rating can be S, A, B, C, D, or E (in order from most to least bonus for the associated skill).

Strength and Dexterity will increase the physical damage of the weapon, whereas Intelligence and Faith will increase the magic damage of weapons. Lightning and Fire weapons do not scale with any stat.

Chaos weapons will also scale with Humanity. This will increase both its physical and fire damage.

The rest of this article is (currently) only relevant to damage. Magic adjust is not covered.

Mechanics
Scaling can be calculated easily from three stats:
 * BaseDamage: The weapon's base damage.
 * Scaling: The scaling percentage of the weapon (eg: A is about 120%; see below).
 * StatRating: The bonus you get from the stat.

From there, the formula is simply: ExtraDamage = ( BaseDamage &times; Scaling ) &times; StatRating

Which makes the total attack rating:

AttackRating = BaseDamage &times; ( 1 + Scaling &times; StatRating )

Example
A 20 strength user, 1 hand wielding a +15 Club:
 * BaseDamage: 182
 * Scaling: A (132%)
 * StatRating: 20 Strength: 40%

AttackRating = 182( 1 + 1.32 &times; 0.4 ) = 278

A 20 strength user, 2 hand wielding a +15 Club:
 * BaseDamage: 182
 * Scaling: A (132%)
 * StatRating: 30 Strength: 62.5%

AttackRating = 182( 1 + 1.32 &times; 0.625 ) = 332

Abstract
One way of seeing scaling is:
 * Weapon has a BaseDamage.
 * Weapon has a BonusDamage that is a percentage of the BaseDamage.
 * Player only get a fraction of that BonusDamage, based on player's stats.
 * Player increases stats, in the goal to get closer to 100% BonusDamage.

Weapon Ratings
Each weapon gets a BonusRating. These are displayed as letters (S-E), where each letter represents a range. The range is pretty wide, so two weapons with the same letter may not actually get the same scaling.

Choas
Chaos weapons scale with humanity. The rating is equivalent to an high "E", 21%, for both physical bonus and fire.

Stat Scaling
The stat scaling for strength and dexterity are equivalent, as are magic and faith. However, strength/dexterity will not match magic/faith.

The scaling starts "strong", and will hit two softcaps. The first is very soft, but the second is very hard. Scaling between any of these caps are linear. Levels below 10 are not taken into account here.

Strength and Dexterity
The strength and dexterity stat grow very fast. They hit a soft cap at level 40, where they have already acquired 85% of their growth.

Magic and Faith
The magic and faith stat grows slower and steadier. They take longer to reach their cap at level 50, where they will have acquired 80% of their growth.

Humanity
Humanity will scale for chaos weapons. Chaos weapons have a bonus rating in regards to humanity of about 20%. The growth is not linear, and not strictly equivalent for the physical and fire damage of weapons.