How does armor reduce damage in League of Legends?

Armor follows the formula damage multiplier = 100 / (100 + armor). At 100 armor a target takes half damage, at 200 armor a third, and so on. The tool applies this multiplier after penetration to mitigate your average hit.

What order do penetration types apply?

League applies percentage armor penetration first, then flat penetration or lethality. The tool follows that order: it reduces the target's armor by the percentage, then subtracts the flat value before computing the damage multiplier.

Why is attack speed capped at 2.5?

League caps attack speed at 2.5 attacks per second for almost all champions. The tool clamps your entered attack speed to that cap so the DPS figure reflects what actually happens in game.

How is crit averaged into DPS?

Average crit factor is 1 + critChance × (critMultiplier − 1). With base crit at 2.0 and 50 percent crit chance, that is 1 + 0.5 × 1.0 = 1.5 times your attack damage per hit on average, which the tool multiplies into DPS.

Does this include abilities or on-hit effects?

No, this calculates pure auto-attack DPS from attack damage, crit, and attack speed. On-hit effects and abilities add separately, but auto-attack DPS is the right baseline for comparing AD-carry builds and items.

League of Legends DPS Calculator

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League of Legends auto-attack DPS depends on more than the raw attack-damage number — crit, the attack-speed cap, and the target’s armor all change the real output. This calculator applies the game’s actual formulas so you can compare ADC builds and items honestly.

How it works

The model layers crit, armor mitigation, and attack speed:

crit factor    = 1 + critChance × (critMultiplier − 1)
avg hit        = attackDamage × crit factor
effective armor= armor × (1 − pctPen) − flatPen
armor mult     = 100 / (100 + effectiveArmor)
DPS            = avg hit × armor mult × min(attackSpeed, 2.5)

Armor reduces incoming damage by 100 ÷ (100 + armor), and penetration lowers the target’s effective armor — percentage first, then flat lethality — exactly as League resolves it.

Example and tips

An ADC with 250 attack damage, 1.4 attacks per second, 50 percent crit chance, and base 2.0 crit damage hitting an 80-armor target lands a strong sustained DPS figure. Adding lethality or percentage penetration raises it by shrinking the armor multiplier, while pushing attack speed past 2.5 gives nothing because of the cap.