This page is effectively a port of the damage calculation tabs on the NGS Verification Sheet. (EN) (JP)

This page will also have very scary looking math. Be warned.

Damage dealt

The base damage of an attack is determined by the following formula.

(W*F)+P-E

W = Weapon Attack
F = Potency Floor modifier
P = Player Base Attack
E - Enemy Defense

The result of this calculation is then modified by percentage modifiers, such as Potency Up, Power Notation, part modifiers, etc.

Attack Cap

If the value of (W*F)+P is higher than the Attack Limit of an enemy's level, then it is set to the maximum attack.
This usually will not occur in normal gameplay until enemies are 40+ levels below the player.

Critical Hits

For Critical Hits, Potency Floor modifier does not occur and the formula simply becomes W+P-E.

Multipliers

oh god