How the Hit & Crit Damage Calculator works
The calculator follows the game's order of operations for a single hit: flat damage, then increased, then more, then critical hits, then the enemy's mitigation.
Checked against Path of Exile 2 version 0.5 on 2026-11-11. ← Back to the calculator
Formula
hit = base × (1 + Σincreased / 100) × Π(1 + morei / 100)
critChance = min(100, (baseCrit + flatCrit) × (1 + incCrit / 100))
critHit = hit × (1 + critBonus / 100) base critBonus = 100%
average = hit × (1 − c) + critHit × c c = critChance / 100
Elemental and chaos hits
r₂ = max(min(r₁, 0), r₁ − penetration) penetration cannot take resistance below 0%
taken = average × (1 − r₂ / 100)
Exposure and curses can make resistance negative, in which case the enemy takes more than the full hit. Penetration is applied afterwards and stops at 0%, so excess penetration against a 0% monster does nothing. Monsters in Path of Exile 2 have no blanket resistance by rarity: most have 0% unless their type or boss definition says otherwise (for example 45% fire on some fire bosses), so start from 0 and enter the specific value.
Physical hits
taken = hitDamage × (1 − reduction)
Armour is evaluated per hit, so a larger hit (such as a crit) is reduced by a smaller percentage. The calculator computes the reduction separately for the normal hit and for the crit and then averages them by crit chance. The constant K was never published by the developer: community testing in December 2024 measured 12, patch 0.1.1 then made armour "approximately 15% more effective", and most current guides use 10 while one still lists 12. The calculator defaults to 10 and lets you switch to 12. Typical monster armour by level: about 1,150 at level 50, 3,900 at 70, 6,900 at 80 and 12,000 at 90.
Worked example
Fire hit, base 100–200, +20–30 added, 150% increased, more multipliers 30% and 20%, base crit 7%, +2% flat, 50% increased crit, crit bonus 140%, enemy at 40% fire resistance with 20% penetration and 10% exposure:
hit = 175 × 2.5 × 1.3 × 1.2 = 682.5
critChance = (7 + 2) × 1.5 = 13.5% → critHit = 682.5 × 2.4 = 1638
average = 682.5 × 0.865 + 1638 × 0.135 = 811.5
resistance′ = 40 − 20 − 10 = 10% → taken = 811.5 × 0.9 = 730.3
What is not included
- Chance to hit (accuracy vs evasion) and blocking — the result is per landed hit.
- Damage conversion and "gain as extra" — enter the final damage of the type you are calculating.
- Ailments and damage over time: ignite, bleed, poison are separate calculations.
- Monster-specific damage taken modifiers (for example "takes reduced damage from critical hits").
Sources and version
- Order of operations (added → increased → more) and additive stacking of increased modifiers: in-game skill tooltips and the community wiki pages on damage modifiers.
- Base critical damage bonus of +100% and flat "+% to Critical Hit Chance" added before increases: poe2db.tw Critical Damage Bonus, items copied from the game (5.00% + 1.4% shown as 6.40%).
- Default maximum resistance 75% and hard cap 90%, monster armour by level, exposure −20%: poe2db.tw pages Maximum Resistances, Monster, Exposure.
- Penetration floor at 0%, exposure and curses going negative, armour formula shape and 90% cap: maxroll.gg damage-scaling and defence guides, mobalytics.gg penetration and armour guides.
- Constants are marked in the source code for re-verification against the 1.0 patch notes on 11 December 2026.
Path of Exile 2 is a trademark of Grinding Gear Games. This site is an independent fan-made tool and is not affiliated with, endorsed by or sponsored by Grinding Gear Games. Game names are used only to describe what the calculators are for. No game art, icons or logos are used. Formulas are compiled from public sources and may lag behind patches — each tool shows the game version it was checked against.