Armor vs Ammo Calculator

Pierce Level vs Armor Class

Every ammo type has a Pierce Level (Penetration stat divided by 10, rounded down). If your Pierce Level is higher than the armor's Class, the round will always penetrate and deal full damage. If they're equal, you'll get partial penetration with reduced damage. If your Pierce Level is lower, penetration chance drops significantly.

Penetration Chance (Under-Pen)

When your Pierce Level is below the armor class, the chance to penetrate follows this formula:

x = ((Armor Class × 10 + 5) − Penetration) ÷ 10

Hit Chance = 1 ÷ 2^x

When your Pierce Level equals the armor class, hit chance ranges from 80% to 100% depending on your exact penetration stat within the level.

Damage Reduction

Even when a round penetrates, armor reduces the damage dealt. Full pen deals ~100% damage, same-level pen deals ~80%, and under-pen rounds deal progressively less — down to about 50% at 4+ levels below.

Durability Matters

As armor takes hits, its durability drops. Lower durability means higher penetration chance for subsequent rounds. This calculator lets you adjust durability to see how a damaged vest performs. Each shot reduces durability by the ammo's Armor Damage stat.

Disclaimer

This calculator uses community-researched formulas. Exact in-game values may differ slightly, especially after balance patches. Use this as a guide, not gospel.