Power level is hero power + 185. Hero power is character level * 10 + total power level of items equipped / 5. The lowest and highest power level are 200 and 835 respectively.

Attack power, stagger power and cleave power are all calculated using a non-linear function that takes character power level. All current sources of "Power" or anything similar affect the output of this function, not the input. This means that Power Level as well as anything that increases damage/stagger/cleave give linear increases.

The only exceptions are headshot damage and critical power which linearly increase ONLY the extra damage from a headshot and/or critical. Refer to the Damage Calculation (headshot/critical boosts) section for more details.

Damage in Vermintide 2 is rounded to the nearest quarter of an integer (i.e. 10.2 would round to 10.25 and 10.1 would round to 10).

Vermintools takes the rounding into account when calculating breakpoints. For example, a 1h axe light attack deals ~9.2 raw damage which rounds to 9.25 damage. Against a stormvermin (39 hp) it'd take 1h axe 5 hits (39 hp / 9.25 damage = 5 hits). To reach the next breakpoint (5 hits -> 4 hits) it would need ~4.8% power vs stormvermin to increase the raw damage to ~9.625 which rounds to 9.75 (39 hp / 9.75 damage = 4 hits).

An attack's cleave is largely controlled by 3 factors. That attack's hit mass profile, power level, and the cleave coefficient in the damage profile.

When an attack starts a swing a cleave value for damage and stagger is calculated. When a mob is hit the mob's hit mass is removed from the cleave value. Once a cleave value reachs 0 that portion stops cleaving. For example, if an attack had a damage cleave value of 10 and hit a mob with a hit mass of 9 its cleave value would be reduced to 1 allowing it to hit one more mob. If the attack has a hit mass profile that multiplies that mob's hit mass by 0.5 then the mob's effective hit mass to that attack would be 4.5 (9 * 0.5 = 4.5) meaning that that attack could damage 3 of those mobs in one swing as opposed to 2. Attacks will typically have different cleave values for damage dealt and stagger.

Damage profiles can have different damage scaling and armor multipliers for each target hit (i.e. first target hit, second target hit, third target hit) in an attack. While some attacks can't cleave two stormvermin, it could be possible to hit a slave rat and then a stormvermin. Although since the stormvermin is the second target hit the attack it would deal less damage than if the stormvermin was the first target.

Some damage profiles use default target for 1st target hit and a target override for 2nd. This causes any target after the 2nd to take the same amount of damage as the 1st target. For example, Falchion light_attack_down "benefits" from this against slave rats with base damage cleave, and a lot of other attacks will "benefit" from it with enough cleave increase. I'd imagine this is because of how the damage profiles are were adapted from Vermintide 1 to Vermintide 2 and the introduction of power level.

Damage profiles have up to 4 target overrides and a default_target defined. That means no damage profile has more than 5 unique damage values for targets hit. Because of this there is only up to 5 breakpoint rows with all excess targets simplified to "+X". Any excess targets will use the same breakpoint as the 5th target.

Vermintide 2 damage calculation is recreated in Vermintools using JavaScript.

This includes the difficulty softcap for power level, power increases (e.g. power vs race/armor, power level, etc), headshot damage boosts, critical power boosts, strength potion, and power boosts.

All sources of power increases are linear damage increases to total damage output.

All different types of power vs are multiplied against each other. The order can be simplified as such:

The 2.0 update for Vermintide 2 claimed to have change power vs race and power vs armor to stack additively (20% + 20% = 40%). However, current releases seem to still be using the old multiplicative method (20% * 20% = 44%).

damage * (1 + (power vs armor type)) * (1 + (power vs race)) * (1 + (power melee/ranged)) * (1 + (generic power)) * (1 + (damage taken debuff))

For example, a 1H Axe normal light attack as ranger veteran with 10% power vs armored, 20% power vs skaven, Last Resort talent (25% generic power) and 5 stacks of Barrage (25% generic power), and Shrapnel active (20%) against a stormvermin would do:

~9.2 * (1 + (.1)) * (1 + (.2)) * (1 + (0)) * (1 + (.25 + .25)) * (1 + (.2))

= ~9.2 * (1.1) * (1.2) * (1) * (1.50) * (1.2)

= ~9.2 * 2.376

= ~21.86 which rounds to 21.75 damage

Power vs armor works against the base armor of a mob. For example, power vs infantry increases damage dealt against a chaos mauler, body and head, despite the head being superarmor. On the other hand power vs armor does not increase damage against a chaos mauler.

Headshot boost and critical power boost modifiers interact with damage differently than power vs modifiers.

Each damage profile for an attack has a boost curve that defines the extra damage from headshots and critical hits. The boost curve's Y cordinate functions as the multiplier for the extra damage from headshots and/or criticals. The Y position is normally a range from 0 to 1 unless a boost curve multiplier defined in the damage profile overrides the maximum value. The X position is a range from 0 to 1. Headshots and criticals each boost X by 0.5. If the target is a monster than headshots only add 0.25 to X.

Originally both headshot boost and critical power increased the X position (to a maximum of 1). However, as of the 1.0.5 update for critical power and the 2.0 update for headshot boost they both affect the extra damage after it's calculated from the boost curve. This makes them both linear increases and simplifies the math.

Headshot boost and critical power increases the extra damage from a respectively headshot or critical hit. That means that if we know exactly how much extra damage is dealt on a critical and headshot critical then calculating the damage increase from critical power would be (extra damage * critical power = increased damage).

For example, an attack deals 40 damage on a normal hit and 80 damage on a critical hit.

80 - 40

= 40

And then we plug in 20% critical power boost in.

40 + (40 * (1 + (.2))

= 40 + 48

= 88

Headshot boost works the same way with headshots as this example.

However, some weapons have a different critical armor multiplier that changes the base damage scaling for critical hits compared to normal hit. This can greatly complicate calculating the extra damage of a critical hit.

For example, if we increased the critical armor multiplier by 50% over our first example we would need to account for the increased base damage when trying to get the extra damage.

60 + (60 * (1 + (.2))

= 60 + 72

= 132

If we just try subtracting the base damage from the critical damage like in our first example to get the extra damage then it would be incorrect.

120 - 40

= 80

40 + (80 * (1 + (.2))

= 40 + 96

= 136

!= 132

This makes it difficult to calculate damage with critical power boost by hand unless we cross reference with other resources.

These examples only serve as a simplified reference to how headshot boost and critical power work. In reality almost every damage profile used in Vermintide 2 has 1 or more of the following that complicates the math: non-linear boost curve, boost curve multiplier, critical armor multiplier.

Vermintide 2 bosses have boss armor that affects the base damage, headshot damage, power boost damage, and backstab damage before they're added together.

While it could be said that fleshy monsters have ~55% damage reduction, it'd be more accurate to say that they take 55% reduced base damage, 50% reduced headshot damage, and 50% reduced power boost damage. This occurs in the final step before the damage sources are added together.

Vermintools doesn't have full support for bosses currently, but does have fleshy monster support for Shade ultimate specifically. It can be reached by appending ?shadeult to this website's link. Note that all monster armor is calculated as if it was boss armor (i.e. gets the damage reduction) and that Shade ultimate is a guarenteed critical hit. As such just ignore non-crit values.

Damage does not snapshot in Vermintide 2. Damage and sources of damage increase are calculated when it's dealt.

This affects any form of delayed damage. For example if 2 shots are fired from a Hagbane with enough power vs to kill a special and then the active weapon is switched to one with less/no power vs against that special rolled on it, it would decrease the damage of the dots' ticks that occur while the weapon with less power vs is active. This is because properties in Vermintide 2 are applied as global buffs, and weapons' properties are only applied if that weapon is active (i.e. currently wielded). This affects any source of delayed damage such as projectiles, dots, and even ultimate skills.

Vermintools does not currently handle delayed damage and active weapons.

In Vermintide 2 buffs/debuffs are applied before damage is calculated.

This means that Slayer's passive, 20% increased damage taken debuff on crits, and others will affect the damage of the hit that procced it. Notable exception is Barrage due to it's unique buff application. The Barrage trait on hit applies a debuff that when that mob is hit again gives a stack of Barrage. That means that even shotgun bash (infinite "cleave") would need to hit the same mob/mobs at least 2 times to gain Barrage stacks.

Vermintools does not currently emulate on hit procs.

Dots in Vermintide 2 are "buffs" applied to a mob that deals damage every tick for it's duration.

Poison and bleed dots are applied on hits that deal damage while burning dots are always applied on hits.

A dot has a defined tick rate, duration, max stacks, and damage profile. Some dots use the same damage profile. When a dot is applied it inherits the attack's scaled power multiplier. This only affects charged attacks like Fireball Staff and Conflag Staff.

Dot ticks have a variance range of -25% to +25% from the base tick rate. The variance is calculated per tick. This causes dots to have inconsistencies with total damage dealt due to losing a tick or more rarely gaining a tick.

Vermintools currently ignores dot tick variance.

Vermintools compiles the attack speed directly from Vermintide 2. While it can simulate most ingame attack speed, a few outliers (hagbane finger roll) aren't supported at this time.

Attacks that have 0 wait time for block/animation cancel are handled by assuming that the attack would be interrupted halfway through the damage window. For example, axe and falchion L1 -> animation cancel has the highest base melee DPS but the animation cancel window starts before the damage window starts. This means that while it is possible to attack that fast, brute forcing animation cancel with a macro wouldn't work with it due to interrupting the attack before the damage window starts and thus dealing no damage.

Combos ending with a animation cancel are hard coded to add a flat .05s (3 frames for 60hz) to the combo speed to simulate the delay from QQ cancel. This can be partially circumvented by repeating the combo multiple times or completely circumvented by ending the combo with a different weapon's action.

Stagger calculation is done on hit against a mob. Some mobs have extra stagger resistance or stagger immunity to certain types during some of their animations. For example, a chaos warrior doing an overhand attack is immune to light, medium, and heavy staggers which effectively means melee weapons cannot stagger a chaos warrior during that animation regardless of stagger strength.

Stagger is increased by power level and stagger power. Headshots and criticals cause the mob hit to ignore it's stagger reduction, which is effectively a flat stagger strength increase that is independant of weapon used or initial stagger strength of the attack.

When a mob is staggered by an attack the following happens:

1. stagger strength is calculated from impact power.

2. if the attack was normal then stagger strength is checked against the mob's stagger thresholds to determine the stagger type, otherwise the stagger type is based directly on the attack (push is 6, pull is 9, etc) and skips step 3.

3. stagger duration is calculated based on the mob's stagger multiplier for that difficulty and multipied by 0.75-1.25 based on how much over the stagger threshold the stagger strength was.

4. stagger duration is increased by a random value of up to 0.25 seconds.

5. stagger level is increased by stagger type or 2, whichever is lowest. This means anything higher than a light stagger will cap the damage bonus.

Additionally, the heavy stagger threshold for a push on a non-staggered mob is double. On the other hand, when a mob is staggered any source of stagger will increase by up to double stagger strength based on current stagger level and the mob's stagger multiplier. Effectively this means that the first push against a mob not staggered requires twice the stagger strength to reach the heavy stagger threshold, but pushes (and any other stagger) against an already staggered mob will have up to double the total stagger strength.

The stagger level is increased by a maximum of 2 for each hit that staggers the mob. This means that any hit with enough stagger strength to reach the medium/heavy stagger threshold will effectively max out the stagger level on a mob.

When a mob is hit and staggered they stay staggered either for the animation duration or the stagger duration, whichever is longer.

The melee weapon trait Opportunist has 2 notable mechanics.

First, Opportunist only works on mobs when they are doing an action. Given that AI seem to be controlled exclusively through actions it is a safe bet that Opportunist is always active.

Second, Opportunist increases the raw power level. Effectively this makes the 50% bonus increase stagger power non-linearly and, assuming 650 hero power, causing the scaled power level to be soft capped on any difficulty below catacylsm.

In lieu of a proper graph, here is a list of the increase stagger power from Opportunist at 650 hero power for each difficulty:

~36% stagger power on cataclysm or higher.

~25% stagger power on legend.

~14% stagger power on champion.

~19% stagger power on veteran.

~16% stagger power on recruit.