Damage Formula Helper
Pick a formula: generic RPG (attack, defense model, resistance, crit), Pokémon Gen V+ (all 16 damage rolls and KO odds) or D&D 5e (dice, hit chance vs AC, crits, advantage, resistance). Every step is shown.
Use the Damage Formula Helper
Combat Parameters
Calculation Breakdown
Defense Efficiency
Damage formulas by game
The formulas this tool implements, labelled by the game that uses them.
| Game / model | Formula | Example |
|---|---|---|
| League of Legends (armor, magic resist) | dmg × 100 ÷ (100 + armor); negative armor: dmg × (2 − 100 ÷ (100 − armor)) | 100 armor → 50% taken |
| Dota 2 (physical armor) | dmg × (1 − 0.06·armor ÷ (1 + 0.06·|armor|)) | 10 armor → 37.5% blocked |
| Pokémon, Generation V+ | (⌊⌊⌊2L÷5+2⌋ × P × A ÷ D⌋ ÷ 50⌋ + 2) × targets × weather × crit × rand(0.85–1) × STAB × type × burn | L75, 65 power, 123 vs 163, STAB, ×4 → 168–196 |
| D&D 5th edition | avg NdX + mod = N(X+1)÷2 + mod; crit rolls 2N dice; hit if d20 + bonus ≥ AC; nat 20 hits, nat 1 misses | 1d8+3, +5 vs AC 15 → 4.35 per attack |
| Subtractive (generic) | max(1, ATK − DEF) | 170 − 80 = 90 |
| Attack ratio (generic) | ATK² ÷ (ATK + DEF) | 170² ÷ 250 = 115.6 |
Sources: League of Legends and Dota 2 community wikis (armor pages), Bulbapedia "Damage" (Generation V onward, worked Glaceon example) and the Pokémon Showdown simulator source, D&D 5e System Reference Document 5.1 (making an attack, critical hits, damage resistance and vulnerability).
Summary
Pick a formula: generic RPG (attack, defense model, resistance, crit), Pokémon Gen V+ (all 16 damage rolls and KO odds) or D&D 5e (dice, hit chance vs AC, crits, advantage, resistance). Every step is shown.
How it works
- Choose a formula tab: Generic RPG, Pokémon (Gen V+) or D&D 5e.
- Generic RPG: enter base damage, attack, the defender's defense and resistance, pick a defense model and set crit chance and multiplier. Add target HP to see hits to defeat.
- Pokémon: enter level, move power, the attacking and defending stat and the modifiers (STAB, type, crit, burn, weather, spread). The tool lists all 16 damage rolls with the game's rounding.
- D&D 5e: enter the damage dice and modifier, attack bonus and target AC. The tool gives hit and crit chance, average damage and expected damage per attack, with advantage, disadvantage, resistance and vulnerability.
- All results update as you type, and the breakdown shows each step of the formula.
Use cases
- Game developers comparing defense models (ratio, subtractive, Dota-style) while tuning combat balance.
- Pokémon players checking whether a move is a guaranteed OHKO or 2HKO.
- D&D players comparing a greatsword with a longsword and shield against a given AC.
- Dungeon masters estimating how many rounds a monster survives.
- Speedrunners calculating one-shot thresholds for boss fights.
- Teaching the difference between multiplicative and subtractive armor.