Damage Formula

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Attack Types: Normal Attack | Charge Attack
Other Damage: Plain Damage | Bonus Damage | Critical Damage | Supplemental Damage
Damage Formula: Basic Concepts | Detailed Formula | Damage Cap | Examples and Guidelines

The damage formula is important to understand once you have completed your first weapon grid and find a new Omega SSR weapon, or draw one in a Premium Draw. Based on what your current weapons are and what summons are available to you, what ultimately increases your damage and overall strength will depend.

Why should I care about a formula?

Knowing your overall strength level isn't trivial in Granblue Fantasy. The Party screen provides some insight through an "Estimated Damage" panel, which is becoming more and more precise, and now allows taking into account summon auras, remaining HP level, turn number and number of foes—but not buffs, debuffs, multiattacks or extra damage types (critical, supplemental and bonus).

However, given the complexity of the system, trial-and-error for grid optimization can quickly become tedious. Therefore, in order to better understand how to build the optimal grid with given resources, as well as how to determine which resources should next be worked towards, it is very useful to know the basic principles behind damage computation.

Base damage

The base damage of a character is a virtual damage value, used for further computations. It can be viewed as the average damage a character will do for each hit of a normal attack, on a normal defense enemy with no buffs or debuffs.

The base damage is based on the character's ATK stat, modified by a boost factor. ATK is simply the sum of all the grid weapons' and summons ATK values, each weapon ATK being modified by an increased 20% if it matches that character's proficiency.

Therefore, in very simple terms, the base damage formula is as follows:

Base Damage = ATK × Total Boost

The Total Boost factor is the multiplication of 4 main boost categories, usually called Elemental, Omega, EX, and Normal. These are completed by other, more specific categories that will not be detailed here (see Detailed Formula to understand the full damage computation).

Total Boost = Elemental boost × Omega ATK boost × EX ATK boost × Normal ATK boost × Other boosts

Boost categories

The value of each boost category is computed using all the modifiers of that category. These modifiers come from weapon skills, what element is used, character bonuses, character skills, etc.

For simplicity's sake in this section, we will consider that characters are neither buffed nor debuffed. Moreover, we will only take into account "flat ATK up" weapon skills, such as Might, which just contribute to the damage boost without taking into account the character's HP level. These skills are identifiable by the Sword icon at the bottom right of the weapon skill icon.


Elemental boost is the simplest to explain :

  • If your element is strong against the enemy's element, your Elemental boost gains +50%.
  • If your element is weak to the enemy's element, your Elemental boost gets -25%.
  • In addition to this, if a main or support summon aura is X% boost to [element] ATK, then your Elemental boost also gets +X%.

Example: you use a Fire team against a Wind enemy (+50%), with a 0★ Ifrit main summon (+40%) and a 3★ Shiva support summon (+140%). Your Elemental boost is computed additively as 100% (base value) + 50% + 40% + 140% = 330%.


Omega weapon skills are present on several farmable weapons, mainly dropped from Omega Raids and Impossible Omega II Raids. You can identify them thanks to the Ω present in the top left of the weapon skill icon. The attack-focused Omega weapons skills will increase your Omega boost.

  • The bonus provided by each weapon depends on the "strength" of its Omega skill (medium or big) and the weapon's skill level, following the Omega table in the Weapon Skills page. All the Omega weapon bonuses then stack additively.
  • Moreover, the six Omega Series SSR summons (Colossus, Leviathan, Yggdrasil, Tiamat, Luminiera and Celeste) have auras that will multiply the modifier of the Omega weapons by a set amount (found in the summon description), as follows:
Omega boost = 100% + (weapons modifiers × summons modifiers)


  • You have five Colossus Cane Omega (Big boost to ATK weapon skill) in your weapons grid, all with a skill level of 4. According to the table, Skill level 4 / Big Boost corresponds a modifier of +9%. Therefore, the five weapons will provide an overall modifier of +45%.
  • You use a 0★ Colossus Omega main summon (+50%) and a 4★ Colossus Omega (+120%) support summon. Your total summons modifier will be 100% (base value) + 50% + 120% = 270%.
  • Your final Omega boost will be 100% (base value) + [45% (weapons) × 270% (summons)] = 221.5%

Note: the Japanese term for Omega is Magna.


EX weapon skills are mainly present on event weapons or side story weapons. You can identify them thanks to the EX present in the top left of the weapon skill icon. The attack-focused EX weapons skills will increase your EX boost.

The bonus provided by each EX weapon depends on the "strength" of its EX skill (small, medium, big or massive) and the weapon's skill level, following the EX table in the Weapon Skills page. All the EX weapons bonuses then stack additively.

Example: You have one Chop-Chop skill level 6 (big modifier) and one True Phantom Demon Blade skill level 15 (massive modifier) in your grid. Following the table, their associated EX modifiers are respectively +11% and +23%. Your EX boost will be 100% (base value) + 11% + 23% = 134%.


If a weapon skill is neither EX nor Omega, it is a Normal weapon skill. These are present on weapons from the Premium Draw, in older events, and on weapons dropped by many raid bosses. You can identify them if there is nothing in the top left of the weapon skill icon, or if there is a II or III. The attack-focused Normal weapon skills will increase your Normal boost.

Normal boost works the same way as Omega boost: the weapons modifiers are found in the the Normal table in the Weapon Skills page, and the Optimus Series summons drawn from the Premium Draw (and their Demi Optimus counterparts) will modify the Normal weapon modifiers. These summons are Agni, Varuna, Titan, Zephyrus, Zeus and Hades.

Additionally, some summons, such as Grand Order, directly add a modifier to your Normal boost.

Example: If you have two level 150 Ixaba at skill level 15 (massive modifier, +22% each) and one 0★ Agni main summon (+80%), your Normal weapon boost is 44%, your Normal summon modifier is 180%, resulting in a Normal boost of 100% + (44% × 180%) = 179.20%

Actual damage

Now that we know how to compute the Base Damage, there remains to transform that into actual damage values. The actual damage value for each hit of normal attacks (not charge attacks or counterattacks) also depends on the following values:

  • the enemy's innate defense
  • the total modifiers to the enemy defense, either debuffs (DEF down) or buffs (DEF up)

The damage done by every hit of a normal attack is then

Per-Hit Damage = Base Damage / (Innate defense × modifiers) [±5%]

The most common innate defense value is 10. Additionally, in most situations, players will try to apply maximal DEF down to the enemy (50%) while dispelling DEF up buffs. In that case and with no other buffs/debuffs, the actual enemy defense drops to 10 × 50% = 5.

Finally, the ±5% corresponds to a random variation of the actual output, computed per hit, to introduce some variability in the numbers you will see on screen.


For detailed information, check the Detailed Formula article. However, here are some elements to introduce the more elaborate concepts.

Are there other Boost types?

Yes, there are.

Some weapon skills contribute to completely separate Boost categories, e.g. Normal Enmity, Normal Stamina, Omega Enmity, Omega Stamina, EX Enmity, Seraphic Weapons skills.

Some contribute to the 4 main Boost categories by complexifying the formulas, e.g. Bahamut Weapons and Ultima Weapons skills.

What about the character skills?

The character skills (active or passive) are very diverse and their impact on the damage formula depends on their type. As for weapon skills, some skills create new multiplicative Boost categories, some contribute to the existing Boosts.

For instance :

  • Anila's skill effect Hidden Tiger, Crouching DragonCharge bar gain is boosted /
    Debuff resistance is boosted /
    ATK is boosted /
    Double attack rate is boosted /
    Attacks made with elemental superiority have a chance to deal boosted DMG
    (Can't be removed)
    is a Normal ATK up modifier and will contribute additively to the Normal boost.
  • Sarunan's skill  Mad VeilAll allies gain 70% Dark CutDark DMG is cut 70%
    Duration: 2 turnsDark Damage Cut.
    and Aurora CrestLight magic is amplified (Max: 5 / Can't be removed)
    At level 95:
    All allies also gain 50% Light ATK UpLight ATK is boosted
    Strength: 50%Duration: 2 turns
    provides Elemental (Light) ATK up to allies. This modifier will be added to the Elemental boost provided by the Elemental Summons and the element superiority bonus.
  • Fif's skill effect Magic TorrentRecovers once from a knockout while in effect /
    ATK is boosted /
    DEF is boosted /
    Double attack rate is boosted /
    Triple attack rate is boosted
    Deals bonus light DMG for one-foe one-ally attacks
    Charge bar is boosted on every turn
    (Can't be removed)
    is a Unique modifier. This means that it creates by itself a completely new Boost category, that will be applied multiplicatively to the Base damage formula.

What's this about multiplication and addition?

Without going too much into detail, stacking multiplicative boosts is usually more beneficial than just adding modifiers to an existing boost, as long as all these boosts have roughly the same potency. This means that for most grids, players will try to fit at least one EX, one Normal and one Omega weapon, independently of what summon they use. Similarly, Unique skills are very sought for, since they will stack multiplicatively to the Base damage and therefore amplify the effect of all other boosts.

However, keep in mind that these are only generic rules, and it can be hard to find the optimal setup when taking into account all the possible weapons skills, character skills and summons. Building Basic Grids is a good way to progress as a player, but fine-tuning complex grids can require experimentation or the use of simulators.

What about Charge Attacks, Chain Bursts, critical hits, counterattacks?

These special attacks also use the Base Damage as basis for computation. Therefore, maximizing your Base Damage will always be a good idea. However, their actual computation involves notions of multipliers, critical chance, number of participants, so refer to the Detailed Formula article for details.