Mechanics

Normal Direct DMG

Note: Applies to all skill DMG that does not trigger an Elemental Reaction and is not of the Lunar or Stellar type.

Amplifying Reaction

Note: Applies to skill DMG that triggers Vaporize or Melt.

Catalyze Reaction

Aggravate Reaction Coefficient: 1.15; Spread Reaction Coefficient: 1.25
Level Multiplier: click "Character Level Multiplier" to jump to the appendix and look up the exact values for Lv. 1–100.

Note: Applies to skill DMG that triggers Aggravate or Spread.

Transformative Reaction

Level Multiplier: click "Character Level Multiplier" to jump to the appendix and look it up.
Note ①: Under normal circumstances transformative reactions cannot CRIT, so there is no CRIT Multiplier. There are, however, a few special cases — for example, Nahida's C2 allows Bloom and Burning reaction DMG to CRIT, and Lauma's (Nascent Gleam) Passive Talent allows Bloom reaction DMG to CRIT. For transformative CRIT effects such as these, the CRIT Multiplier value does not come from the character's stats, but from the specific value granted by the effect.
Note ②: Applies to DMG dealt by Bloom (non-Lunar), Electro-Charged, Superconduct, Overloaded, Swirl, Burning, and Shatter reactions.

Lunar Reaction

Level Multiplier: click "Character Level Multiplier" to jump to the appendix and look it up.
Base Boost: the reaction Base Boost provided by 5-star Moonsign characters (Lunar talent) based on one of their own stats.
Note ①: After repeated Moondrift Harmony tests with C1 Linnea, the reaction coefficient and contribution weights provided by HomDGCat were wrong; this page is authoritative. For the Lunar-Charged reaction, or for Lunar-Crystallize without C1 Linnea, HomDGCat's algorithm gives the same result as the algorithm here.
Note ②: Applies to the Lunar-Charged reaction (Thundercloud DMG) and the Lunar-Crystallize reaction (Moondrift Harmony DMG). The Dendro Core explosion DMG produced by the Lunar-Bloom reaction is normal Bloom DMG rather than Lunar-Bloom DMG, so this algorithm does not apply to it. Lunar DMG dealt by skills does not count as triggering a Lunar reaction, so this algorithm does not apply to it either.

Lunar Direct DMG

Base Boost: same as Lunar Reactions (provided by the Passive Talent of 5-star Moonsign characters).
Note: Applies to Lunar DMG dealt by skills (Lunar-Charged skills, Lunar-Bloom skills, Lunar-Crystallize skills).

Stellar Glimmer

Reaction Overview: When Anemo comes into contact with Cryo and certain conditions are met, a special Stellar Swirl reaction is triggered, creating a vortex. The vortex detonates after 4.5s, dealing one instance of Cryo Stellar Swirl reaction DMG. While the vortex is present, every further Stellar Swirl reaction triggered will deal one instance of Anemo Stellar Swirl reaction DMG and raise the vortex's level by 1. The vortex can be raised to level 6 at most, and it detonates automatically once it reaches max level. In addition, when the vortex detonates and deals DMG, its level is reset to zero.

Note ①: For the Cryo Stellar Swirl reaction, the 1st Contribution DMG is always contributed by a Cryo character and the 2nd Contribution DMG by an Anemo character; for the Anemo Stellar Swirl reaction, the 1st Contribution DMG is always contributed by an Anemo character.

Level Multiplier: click "Character Level Multiplier" to jump to the appendix and look it up.
Base Boost: Sandrone's and Odette's Passive Talents provide a reaction Base Boost based on their own ATK — at 2000 ATK they reach the 14% Base Boost cap, so the Base Boost Multiplier is 1.14; the Traveler (Cryo)'s Passive Talent provides a reaction Base Boost based on their own ATK — at 2000 ATK they reach the 7% Base Boost cap, so the Base Boost Multiplier is 1.07.
Note ①: The EM Multiplier of Stellar reaction DMG still follows the EM Multiplier formula used for Lunar reactions; the only difference is that the Elemental Reaction that the Additional EM Multiplier is based on is a Stellar reaction instead of a Lunar reaction.
Note ②: This algorithm applies to DMG dealt by the Stellar Swirl reaction (vortex).

Stellar-Conduct Direct DMG

Reaction Overview: When Cryo comes into contact with Electro and certain conditions are met, a special Stellar-Conduct reaction is triggered, and the nearby area is briefly transformed into a wondrous "Polestar Field". When opponents within the "Polestar Field" are affected by Cryo or Electro application, the "Polestar Field" freeze-stores this overflowing elemental power and releases all of the stored elemental power every 4s, converting it into a buff for all characters within the field: they gain Cryo and Electro DMG Bonus, and the base Reaction Coefficient of the Stellar-Conduct reaction DMG they deal is increased, lasting 4s. In addition, opponents within the Polestar Field have their Physical RES reduced.

Reaction Coefficient and DMG Bonus: after a Stellar-Conduct reaction is triggered, the number of times opponents are affected by Electro or Cryo application during each 4s window is recorded, up to 10 times. When the recording ends, the Stellar-Conduct reaction coefficient and the Electro and Cryo DMG Bonus for the following 4s are increased. The rules are as follows:
· Recorded count = 0: Reaction Coefficient = 1.00; Electro and Cryo DMG Bonus = 20%
· Recorded count = 1: Reaction Coefficient = 1.45; Electro and Cryo DMG Bonus = 29%
· Recorded count > 1: for each additional record, +0.05 Reaction Coefficient and +1% DMG Bonus
(12 records reach the maximum: Reaction Coefficient = 2.0; Electro and Cryo DMG Bonus = 40%)

Base Boost: Sandrone's and Odette's Passive Talents provide a reaction Base Boost based on their own ATK — at 2000 ATK they reach the 14% Base Boost cap, so the Base Boost Multiplier is 1.14; the Traveler (Cryo)'s Passive Talent provides a reaction Base Boost based on their own ATK — at 2000 ATK they reach the 7% Base Boost cap, so the Base Boost Multiplier is 1.07.
Note ①: The EM Multiplier of Stellar-Conduct DMG still follows the EM Multiplier formula used for Lunar reactions; the only difference is that the Elemental Reaction that the Additional EM Multiplier is based on is a Stellar-Conduct reaction instead of a Lunar reaction.
Note ②: Stellar-Conduct DMG is not a single Cryo DMG or Electro DMG instance, but is decided by the trigger; it can therefore be either Cryo DMG or Electro DMG, and the only difference is that the RES Multiplier is based on a different element type — keep this in mind.
Note ③: This algorithm applies to Electro Stellar-Conduct DMG and Cryo Stellar-Conduct DMG dealt by skills.

Stellar Swirl Direct DMG

Note: The Reaction Coefficient of the Stellar Swirl reaction is always 1, so it can be treated as if there were no Reaction Coefficient Multiplier.