In a major update to my Damage Calculator, I've united constitutive bonuses from the Assault and Eidolon Effects Calculator together with temporary buffs. Players can now directly observe how buffs like Attack Up affect damage output for specific team compositions. For example, the value of ATK up decreases with increasing assault skill and character attack up from eidolons, and increases with elemental advantage.
I also revamped the Damage Received section to be more useful and intuitive.
Planned for next update: Factoring in uptime of buffs / debuffs, the effect of healing on party longevity (in combination with damage reduction).