Damage Calculator

Every hit follows one chain: DMG = ATK_total × Skill% × (1+ΣBonus) × (1+ΣDeepen) × Crit × DEF-mod × RES-mod. ATK_total combines base resonator ATK and weapon ATK, then applies ATK% plus flat ATK from Echo substats and buffs. Skill% is the multiplier printed on the skill itself, DMG Bonus stacks damage from the same source, and Deepen is a separate amplifier that multiplies on top of Bonus rather than adding to it.

Two DMG Bonus sources of the same type add together before the formula applies them: 30%+30% becomes one 60% multiplier. But a 30% Bonus and a separate 30% Deepen multiply against each other instead: 1.3 × 1.3 = 1.69, a 69% swing rather than 60%. Mixing up which numbers stack additively and which multiply is the single biggest source of wrong damage math.

Crit Rate and Crit DMG follow a rough 1:2 build ratio, starting from a base 5% Crit Rate and 150% Crit DMG, with most endgame builds pushing Crit DMG toward roughly 200-240%. The enemy's DEF cuts damage through a DEF-mod near 52% at matched level brackets (shifting about ±2% per bracket gap) — this figure comes from community measurement rather than an official closed formula, so treat it as an estimate you can nudge by hand. RES works differently: getting hit on an element the enemy resists cuts damage by roughly a third, while a negative RES value adds extra damage instead.

The calculator above is built to answer one question: is this upgrade actually worth it? Plug in your current build, note the estimated hit, then swap in a second echo set or a second weapon and compare the two numbers side by side. That direct comparison is far more reliable than eyeballing a substat sheet, and it costs nothing — do it before spending Tuners, Waveplate, or Astrite on a build that only looks better on paper.