Battle Brothers Damage Calculator

How the Calculation Works

Simulation

Each calculation runs 20,000 Monte Carlo simulations. Every simulation randomly rolls damage, headshot chance, and armor loadout, then counts hits until the enemy dies. Results are averaged across all runs.

Attacker Traits and Perks

We model all traits, perks, backgrounds, injuries, and status effects that affect damage output. Damage multipliers (Huge, Drunkard, Killing Frenzy, etc.) stack multiplicatively. For example, Huge (x1.10) combined with Drunkard (x1.10) results in x1.21 total damage. Perks like Duelist add to armor piercing additively (+25%). The labels in the calculator indicate which type each modifier is.

Weapon

Each hit rolls two independent random values within the weapon's damage range: one for HP damage and one for armor damage. Armor piercing determines how much HP damage bypasses armor, while remaining armor absorbs part of the incoming damage.

Skills

Each weapon has one or more skills with different effects. Some modify damage, armor piercing, or apply bleeding. Hybrid strategies like "Cleave into Decap" switch skills mid-fight to maximize damage potential.

Enemy Defender Perks

The simulation applies Battle Forged (armor damage reduction), Nimble (HP damage reduction), Steel Brow (no headshot bonus), and Nine Lives (survives first lethal hit) automatically based on the selected enemy. Enemies can have many more perks, but only these four affect hits to kill, injure, or morale.

Racial Traits

Some enemies have immunities to bleeding, morale checks, or injuries. Others have more complex resistances to certain attacks. All of these are listed as Racial Traits in the enemy stat card. For enemies with damage resistances, you can click the trait name to see the full resistance table.

Three groups have damage resistances:

• Alps, Ancient Dead, and Ifrits have resistances to ranged weapons and piercing melee attacks. Alps are "Existing Partly in Dreams", Ancient Dead are "Resistant to Ranged Attacks", and Ifrits have the "Sand Golem" trait. The three are similar but slightly different.
• Schrats and Serpents have resistances to ranged attacks, but unlike the first group they are not resistant to piercing melee. Schrats also reduce all incoming damage to 30% while their root shield is up, but this is not modeled. You should destroy the shield with axes first anyhow.
• Fallen Betrayer takes 25% less armor damage, making his armor degrade slower.

Enemy Armor Loadouts

Enemies with variable equipment have multiple possible armor loadouts. Each simulation randomly picks a body armor and helmet combination weighted by spawn probability. For example, a Brigand Raider has 4 body armor options and 6 helmet options, resulting in 24 different possible loadouts. This means results reflect the full range of encounters.

Head and Body Armor

Each hit targets either the head (25% base chance) or the body (75%). Headshots hit the helmet, body hits hit body armor. Armor absorbs damage and degrades over multiple hits. Headshots deal 150% HP damage.

Damage Calculation

The damage formula has three scenarios:

• No armor on the body part. Damage directly removes HP.
• Armor survives the attack. One roll determines armor damage, a separate roll determines armor-piercing HP damage. The HP damage is reduced by 10% of remaining armor.
• Armor destroyed in the process. The excess damage that wasn't needed to destroy armor flows through as direct HP damage, combined with the armor-piercing portion.

Hits to Trigger Morale Check

A morale check is triggered when a single hit deals at least 15 HP damage. With the Fearsome perk, the threshold drops to just 1 HP damage, triggering morale checks every hit that penetrates armor. We simulate when the first morale check occurs, but not whether morale actually drops.

Hits to Injure

An injury occurs when a single hit deals HP damage equal to or greater than 25% of the enemy's maximum HP. Head injuries require 31.25% of max HP (25% × 1.25). Crippling Strikes lowers all injury thresholds by 34%.

Bleeding

Cleave and Whip skills apply bleeding (5 per turn, 10 with Weapon Mastery). Bleeding only triggers when the hit deals at least 6 HP damage. Bleed is a 2-turn stacking effect that ticks on the enemy's turn. Multiple bleeds from consecutive hits overlap, so the second qualifying hit onwards causes two stacks to tick simultaneously. Resilient halves bleed duration to 1 turn, preventing stack overlap. Nine Lives clears all bleed.

Hits to Kill

The average number of hits needed to reduce the enemy's HP to zero.

Noble House Equipment

Noble faction enemies (Footman, Billman, Arbalester, etc.) spawn with equipment that varies by noble house. Different houses use different armor styles (kettle hats vs flat tops vs nasal helmets). Since the noble house is random, we average across all houses to produce a single combined loadout table.

DLC Equipment

Some enemies gain additional armor options when DLCs are active (Warriors of the North, Blazing Deserts, etc.). Our loadout data assumes all DLCs are installed. Without certain DLCs, some enemies have fewer equipment options and slightly different average armor values.

Not Modeled: Lower Enemies and Champions

Some enemies can spawn as lower versions (e.g. lower Brigand Raider) with slightly reduced stats and on average less armor. For example early-game Brigand Parties can have a mixture of regular Raiders and lower Raiders. But overall these lower enemies are rare and only account for roughly 15% of all encounters, so they are not modeled here.

Champions are buffed enemies with more HP, higher damage, better defense and a named item. If the named item is a Named Armor, it can have significantly higher durability. This changes survivability drastically, so we do not model Champions.

Caching

Results are cached per unique matchup. The first time you run a specific combination of weapon, skill, enemy, and modifiers, the simulation runs fresh. Subsequent requests for the same matchup return the cached result instantly. If we update the damage engine, the cache is cleared so all matchups use the latest formulas.

Not Modeled: Bosses

Bosses like the Kraken and the Horned God in Hunting Ground have extremely high HP and armor pools. These fights are too unique to produce meaningful simulation results, so we do not model them.