Combat calculator

How it is worked out

Chance to hit (melee)

35 + melee attack − melee defence, kept within 8–90%

Source: _kv_rules: melee_hit_chance_base, _min, _max; the wiki's Combat page

Armour

blocks a random share of base damage between half the armour and the full armour (as %), never more than 100%; armour-piercing damage goes through. An explosion has both parts: armour blocks its base explosive damage the same way, its armour-piercing explosive damage goes through. Above 100 armour the average rises by 0.25% a point up to 100% at 200.

Source: _kv_rules: armour_roll_lower_cap = 0.5; the game's missile-strength description (“armour-piercing damage is always applied, base damage can be blocked by armour”); projectiles_explosions: detonation_damage, detonation_damage_ap; the wiki's Combat and Armour pages

Shield (missiles)

a shield facing the shots blocks its missile block chance of small-arms missiles: arrows, crossbow bolts, bullets, javelins, throwing axes, slings. Artillery and misc projectiles (cannons, mortars, catapults, bolt throwers, the Stegadons' bows and blowpipes, Scourgerunner harpoons, the Iron Daemon…) ignore it. The game doesn't say whether grenades are blocked: they are counted as blocked.

Source: the game's Missile Block Chance description (“block (non-artillery) missiles”) and Shielded tooltip (“small-arms missile fire”); CA's note on projectiles.category (“some categories like artillery and misc ignore shields”)

Bonus vs large / infantry

adds its value to melee attack and to weapon damage, split between base and armour-piercing like the weapon's own; large targets are those bigger than a man on foot (cavalry count)

Source: the wiki's Statistics page; entity size from battle_entities

Charge bonus

adds its value to melee attack and damage (split the same way) when charging; it fades over 13 s, so this is the first blow

Source: the game's charge-bonus description; _kv_rules: charge_decay_duration; the wiki's Charge Bonus page

Resistances

add up and cap at 90%: ward save (all damage), physical (not against magical attacks), missile (missiles only), fire resistance or weakness (flaming attacks only)

Source: _kv_rules: ward_save_max_value; the wiki's Damage channel page; CA on Warhammer III's magical attacks

Magic barrier (Tzeentch)

a unit's barrier takes damage before its health: Pink Horrors 1,400 on 6,400 health, Kairos Fateweaver 1,200, a Lord of Change 800. It recovers only while the unit isn't taking damage, so in a fight it counts once, as hit points taken first. Barrier that skills, items or effects add on top (the Mark of Tzeentch's, a Warshrine's) is not counted.

Source: main_units.barrier_health; the game's Magic Barriers help (“Damage taken … will be first applied to its magical barrier”, “recovers slowly over time when the unit it protects is not under attack”)

Checked against the wiki's worked examples (Temple Guard against Rat Ogres, the Swordsmen charge, fire weakness) and the game's constants in _kv_rules.

What it leaves out

• Time in melee: how often a model swings depends on its animations and how many models reach the fight, so the calculator counts hits and attacks, not seconds.
• Missile accuracy, range and cover: the missile numbers assume every shot hits, so they are the best case.
• Impact damage of a charge, mass, knock-downs, splash attacks of big monsters, bracing against charges.
• Flanking and rear attacks, fatigue, rank, leadership, skills, items, abilities and spells.

Unit numbers: compare units · counters · base stats from the game's tables (WH3-Dump).