Pokémon Damage Calculation Explained: Formulas, Modifiers, STAB, Types, and Competitive Optimization

⚔️ Damage calculation basics

Every damaging move’s final output starts with a base formula, then applies multiple multiplicative modifiers in a specific order.

• Offensive stat: Attack for physical moves, Special Attack for special moves (some moves use the other stat).
• Defensive stat: Defense for physical moves, Special Defense for special moves (some moves use the other stat).
• Base power: The move’s inherent strength before modifiers; can change due to effects like Technician, Charge, or weight-based moves.
• Target HP: Damage is subtracted from this; HP itself doesn’t affect the calculation.

🧮 Standard damage formula (Gen V+)

Damage = $[\frac{(2\times \mathrm{Level}÷5+2)\times \mathrm{Power}\times (\mathrm{Attack}÷\mathrm{Defense})}{50}+2]$

× Targets × Weather × Critical × Random × STAB × Typing × Burn × ZMove × TeraShield × Item × Screens × Other

Formula explaination: First, the formula takes the attacker’s level, the move’s base power, and the ratio between the attacker’s offensive stat and the defender’s defensive stat to get a “base damage” number. Then it applies a series of multipliers for battle conditions. These include things like the number of targets hit, power boosts, weather effects, critical hits, randomness, Same‑Type Attack Bonus (STAB), type effectiveness, status effects like burn, and other situational modifiers. All of these stack to produce the final damage dealt. Finally, the resulting damage is subtracted from the target’s current HP to determine its remaining HP. Here are all parameters explained:

• Attack and Defense: Damage scales with the ratio (attack / defense) of the attacker’s relevant offensive stat (attack/special attack) to the defender’s matching defensive stat (defense/special defense). Note that increased or decreased stages of the (special) attack/defense stats are factored in here since the ratio changes.
• Level: Higher level increases damage because level is multiplied early in the formula.
• Stat exceptions: Some moves use different stat pairings (e.g., Psyshock uses Special Attack vs. Defense), so check move-specific rules.
• Targets: 0.75 if hitting multiple targets in Doubles, else 1.
• Weather: Rain boosts Water moves ×1.5, Sun boosts Fire ×1.5; opposite types are halved.
• Critical: ×1.5 (×2 in Gen V and earlier) unless blocked by effects like Battle Armor.
• Random: Random Nr between 0.85 and 1.00. This introduces randomness to the damage calculation.
• STAB: ×1.5 if move matches user’s type, ×2 with Adaptability. When Terastallized into an original type STAB becomes 2× (2.25× with Adaptability). If Terastallized into a new type STAB becomes 1.5× while still having STAB on your original type(s) (you will lose Adaptability bonus on original types).

Example 1: A Water/Flying Pokémon while Terastallized into Water will apply a 2× STAB using a Water‑type move (from matching Tera type) and 1.5× STAB when using Flying type move (still has original STAB).

Example 2: A Normal/Electric Pokémon with Adaptability after Terastallizing into Water will apply a 1.5× STAB multiplier using an Electric‑type or Normal move (still having original STAB). Using a Water type move will result in 2× STAB multiplier (Adaptability + Terra).

• Typing: A multiplier based on the attackers move type against the defenders Pokémon typing. Can be 0×, 0.25×, 0.5×, 1×, 2×, 4×, or even 8× with special conditions (like getting extra type with Forest's Curse move).
• Burn: Halves physical damage unless user has Guts Ability or uses Facade (Gen VI+).
• ZMove: If ZMove or Max Move ×0.25 if blocked by Protect-type moves.
• TeraShield: Raid boss shield multipliers (0.2–0.75×).
• Screens: Moves like Reflect that halves damage from physical and Light Screen which halves damage from special moves (⅔ multiplier in multi‑battle formats), unless bypassed by certain abilities or effects.
• Items: Multipliers from held items such as Life Orb (×1.3 damage), Choice Band/Specs (×1.5 to one offensive stat), or Expert Belt (×1.2 on super‑effective hits).
• Other: Includes ability/move-specific boosts or reductions (e.g. Multiscale, Glaive Rush).

Example: A Lv.50 Fire/Flying Pokémon using a 100 BP Physical Fire‑type move under harsh sunlight will multiply the base result by 1.5 (STAB) × 4 (type advantage against Grass/Steel target) × 1.5 (sun boost) = 9X multiplier (We assume random multiplier is 1 here)

Attacker attack stat = 100
Defender defense stat = 120

((( 2 * 50 / 5 + 2) * 100 * (100 / 120)) / 50) + 2 = 39 (Rounded up)

Final damage = 39 * 9 = 351

📊 Common damage modifiers

• Abilities: e.g., Huge Power doubles Attack, Thick Fat halves Fire/Ice damage, Sniper boosts critical hits to ×2.25.
• Items: e.g., Life Orb (×1.3 damage), Choice Band/Specs (×1.5 to one stat), Expert Belt (×1.2 on super-effective hits).

📌 Strategy tips

• Stack multiplicative boosts (STAB + item + ability + weather) for massive spikes.
• Exploit 4× or higher weaknesses for guaranteed OHKOs even with moderate base power moves.
• Use weather or terrain to swing type matchups in your favor.
• Account for the random factor when planning close KO ranges.
• Remember that critical hits ignore certain stat drops and defensive boosts.

🕰️ History of damage calculation changes

Core damage formulas and brief notes on what changed in each generation:

Generation I

Damage = $[\frac{(2\times \mathrm{Level}\times \mathrm{Critical}÷5+2)\times \mathrm{Power}\times (A÷D)}{50}+2]$

× STAB × Typing × Random

• Random factor = 217–255 ÷ 255 (~85.1–100%).
• Crits ignore stat changes and some effects

Generation II

Damage = $[\frac{(2\times \mathrm{Level}÷5+2)\times \mathrm{Power}\times (A÷D)}{50}\times \mathrm{Inner\; multiplier}+2]$

× Weather × STAB × Typing × Random × Other

Inner multiplier = Item × Critical

• Badge boosts in single‑player; weather modifies damage.
• Random factor standardized to 85–100%.

Generation III

Damage = $[\frac{(2\times \mathrm{Level}÷5+2)\times \mathrm{Power}\times (A÷D)}{50}\times \mathrm{Inner\; multiplier}+2]$

× Critical × STAB × Typing × Random × Other

Inner multiplier = Burn × Screen × Targets × Weather × FF

• Targets is a Spread move penalty (×0.5 in multi battles when using move that hits multiple targets, 1 in singles)
• Burn 0.5 multiplier for physical moves unless Guts.
• Flash fire (FF) introduced 1.5× multiplier.

Generation IV

Damage = $[\frac{(2\times \mathrm{Level}÷5+2)\times \mathrm{Power}\times (A÷D)}{50}\times \mathrm{Inner\; multiplier}+2]$

× Critical × Item × Random × STAB × Typing × Other

Inner multiplier = Burn × Screen × Targets × Weather × FF

• Multi moves got stronger. Spread move penalty in multi battles when using move that hits multiple targets changed from 0.5 to 0.75.
• Physical/Special split by move not by type.

Generation V

• Modern damage calculation formula introduced (formula in the main article)

Generation VI

• Critical hit multiplier reduced from ×2 to ×1.5 in later gens.
• Burn no longer halves damage for Facade.

Generation VII

• Z‑Moves bypass some damage reduction effects.

Generation VIII

• Dynamax moves have fixed base power and secondary effects.

Generation IX

• Terastallization changes STAB rules and can stack with original typing.
• New multipliers like Glaive Rush and Tera Raid Shields.