Mechanic

Armour

Armour reduces applicable damage from Hits. By default it applies only to Physical Hit damage, and its reduction depends on the raw damage of each Hit rather than providing one fixed percentage.

0.5.4d

Current data

Catalog version 0.5.4d

No direct 0.5 patch change is linked to this page. The displayed values are current for catalog version 0.5.4d.

What Armour does

Current rules

For ordinary Physical Hit damage, reduction is Armour divided by Armour plus ten times the raw Physical damage of that Hit, capped by the 90% total Physical Damage Reduction maximum. This makes Armour much stronger against repeated small Hits than one large Hit. Armour does not mitigate damage over time.

Use the Hit-specific formula: For an applicable Hit, Armour reduction equals Armour divided by Armour plus ten times the raw damage of that Hit. The calculation uses the applicable damage component before that Armour reduction is applied.
Armour normally applies to Physical Hits: Armour normally mitigates Physical damage from Hits. It does not mitigate damage over time, including the damage-over-time portion of Bleeding.
Every Hit is calculated separately: The raw damage of each Hit is compared with the current Armour value. Ten Hits of 100 damage are mitigated as ten small Hits, not as one combined 1,000-damage Hit.
The useful ratios are predictable: Armour equal to 5 times the Hit prevents about one third, 10 times prevents one half, 20 times prevents two thirds, 30 times prevents three quarters, and 90 times reaches 90% reduction.
Total reduction is capped: Total Physical Damage Reduction from Armour and applicable additional Physical Damage Reduction cannot exceed 90%. Since 0.4.0, Armour also cannot reduce a Hit to zero damage; at least 1 damage remains.
Other damage types require explicit wording: Armour applies to Elemental or Chaos damage only when an explicit modifier makes it do so. The Armour calculation is then performed independently for each applicable damage type in the Hit.
Armour Break changes the rating first: Armour Break subtracts from the target's Armour before later Hits are mitigated. Fully Broken Armour is a separate state with additional interactions, including increased Physical Hit damage taken by enemies.
The character-sheet percentage is an estimate: A displayed estimated reduction must assume a reference Hit size. Actual reduction changes for every incoming Hit because its raw applicable damage is part of the formula.

Armour needed for a raw Hit

8 cases

33% reduction

Armour equal to 5 times the raw applicable Hit. A 1,000 Physical Hit needs about 5,000 Armour.

Related: Physical, Hit

50% reduction

Armour equal to 10 times the raw applicable Hit. A 1,000 Physical Hit needs 10,000 Armour.

Related: Physical, Hit

66% reduction

Armour equal to 20 times the raw applicable Hit. A 1,000 Physical Hit needs about 20,000 Armour.

Related: Physical, Hit

75% reduction

Armour equal to 30 times the raw applicable Hit. A 1,000 Physical Hit needs 30,000 Armour.

Related: Physical, Hit

90% reduction

Armour equal to 90 times the raw applicable Hit reaches the normal total reduction cap. A 1,000 Physical Hit needs 90,000 Armour.

Related: Physical, Hit

Damage over time

Armour does not apply. Use the relevant resistance, damage reduction, or damage-taken modifier instead.

Related: Bleeding, Resistances

Armour Break

Subtracts Armour from the target and can produce Fully Broken Armour. The exact break amount and payoff belong to the Armour Break mechanic.

Related: Armour Break, Armour Breaker

Converted Evasion

Iron Reflexes converts all Evasion Rating to Armour, replacing avoidance from that rating with Hit-size-based mitigation.

Related: Evasion, Iron Reflexes passive

Rare monster modifiers

1 linked

Armoured

100% increased Armour.

Limits and exceptions

7 rules

Armour is not a fixed percentage and should not be read as one.
It does not mitigate damage over time.
Large hits require much more Armour to reach the same reduction percentage as small hits.
Armour normally applies only to Physical Hit damage.
An effect that makes Armour apply to another damage type does not make the damage Physical.
Armour and additional Physical Damage Reduction share the 90% total reduction maximum.
Armour cannot reduce an applicable Hit below 1 damage.

Related mechanics

MechanicHit

A Hit is an instantaneous damage event. Any damage that is not damage over time is Hit damage, whether it comes from an Attack, a Spell, Thorns, or another effect.

MechanicDamage

Damage is classified on three independent axes: source, delivery, and type. A component can come from an Attack, Spell, Thorns, or another source; deal a Hit or damage over time; and deal Physical, Fire, Cold, Lightning, or Chaos damage.

MechanicRunic Ward

Runic Ward protects the final point of Life. When damage would reduce Life to 0, Life stops at 1 and current Runic Ward absorbs the remainder. The character still dies if the remaining damage is greater than the Ward available.

MechanicEvasion

Evasion Rating grants an entropy-based chance to Evade enemy Hits completely. The actual chance compares the defender's Evasion Rating with the Accuracy Rating of the attacker.

MechanicEnergy Shield

Energy Shield is a rechargeable defensive resource that normally protects Life. Damage is mitigated first, then removes Energy Shield before Life unless the damage or another effect explicitly bypasses it.

MechanicArmour Break

Armour Break lowers a target's Armour by a specified amount. Reaching 0 applies Fully Broken Armour, which removes the target's Armour benefit and has additional effects against monsters.

MechanicReturning Projectiles

Returning Projectiles travel back to the entity that originated them after reaching the end of their travel or hitting their final target.

MechanicPhysical

Physical damage is one of the five Damage Types. It is the most common and the only one reduced by Armour, rather than by a Resistance.

MechanicAttributes

Strength, Dexterity, and Intelligence are the three primary Attributes. They provide inherent bonuses and are used to meet Equipment, Skill Gem, and Support Gem requirements.

MechanicDeflect

Deflection Rating gives a chance to Deflect damage from Hits. A normal Deflection prevents 40% of the Hit damage, while the chance depends on your Deflection Rating and the attacker's Accuracy Rating.

MechanicIron Reflexes

Iron Reflexes converts all Evasion Rating into Armour. The converted base value scales as Armour rather than Evasion, trading ordinary Evasion Rating avoidance for Armour's hit-size-dependent damage reduction.

MechanicRunefather's Boast

Runefather's Boast is a stacking Buff granted by Eyes of the Runefather when you kill an enemy affected by Runefather's Challenge. Each stack grants +1 Armour, +1 Evasion Rating, and +1 Stun Threshold.

MechanicShrine

Shrines are Precursor Artifacts surrounded by worshipping monsters. Defeat every Shrine Worshipper, click the Shrine, and its effect becomes your buff for a base duration of 45 seconds.

MechanicMage's Legacy

Mage's Legacies are fourteen possible bonuses rolled in Mageblood's four Legacy slots. Each distinct Legacy grants one always-active bonus while the belt is equipped. Repeated names do not stack directly; instead, every duplicate increases the effect of all distinct Mage's Legacies on that belt.

MechanicItem Armour

Item Armour is the Armour value printed on an individual item after that item's Quality and local Armour modifiers are applied. It is a value that other effects can read. It is not the character's total Armour and does not itself describe how much Physical damage a Hit will lose.

MechanicUnbound Potential

Unbound Potential is a stacking buff created by The Unleashed body armour. It converts the Runic Bindings built by Spell Hits in Human form into increased Damage, Armour, and Energy Shield for a shapeshifted character.