Armour

For equipment classified as armour, see Armour (equipment).

For the basic passive skill, see Armour (passive skill).

Armour is a form of defence that mitigates incoming physical damage from hits when all avoidance forms have failed.

Along with evasion and energy shield, armour is one of the three defence types that can implicitly appear on equipment. Unlike resistance, armour has diminishing returns as it's effectiveness is based on the magnitude of incoming physical damage (multiplied by 10). As a result armour is most effective in mitigating small hits (i.e. 50% and better reduction for initial damage less then a tenth of the armor value) and least effective in mitigating very large hits (where it's absolute reduction can at most be one tenth of the armor value).

Armour rating can be increased by wearing equipment, taking certain passive skills, using spells such as Molten Shell, and drinking a Granite FlaskGranite FlaskLasts 4.00 Seconds
Consumes 30 of 60 Charges on use
+1500 to ArmourRequires Level 27Right click to drink. Can only hold charges while in belt. Refills as you kill monsters..

Basalt FlaskBasalt FlaskLasts 5.00 Seconds
Consumes 40 of 60 Charges on use
20% more ArmourRequires Level 40Taunts nearby Enemies on useRight click to drink. Can only hold charges while in belt. Refills as you kill monsters. grants additional physical damage reduction.

Supposedly the most armour monsters have in the game is about 983.

Mechanics

Physical damage reduction from armour only mitigates physical damage from hits. It falls under the modifier #% additional Physical Damage Reduction when Hit. Physical Damage Reduction is capped at Template:SMW character query%.

Elemental damage and damage over time are not mitigated by armour, because armour only mitigates physical damage from hits. Bleed is a damage over time debuff that is based on the initial physical hit, armour would reduce the initial hit but not the damage over time. However both the initial hit and the damage over time can be mitigated with other sources for example Basalt FlaskBasalt FlaskLasts 5.00 Seconds
Consumes 40 of 60 Charges on use
20% more ArmourRequires Level 40Taunts nearby Enemies on useRight click to drink. Can only hold charges while in belt. Refills as you kill monsters. or endurance charges because they don't only apply to hits.

rule of thumb

• To prevent one third of damage, you need armor 5 times the damage (e.g. 500 Armor for 100 damage)
• To prevent half of damage, you need armor 10 times the damage (e.g. 1000 Armor for 100 damage)
• To prevent two thirds of damage, you need armor 20 times the damage (e.g. 2000 Armor for 100 damage)
• To prevent three quarters of damage, you need armor 30 times the damage (e.g. 3000 Armor for 100 damage)
• To prevent 90% of damage, you need armor 90 times the damage (e.g. 9000 Armor for 100 damage)

Formulas

For a step by step calculation of formulas, see Armour/math.

The amount of physical damage reduction is a function of armour rating and the physical damage taken.

Relative Physical Damage Reduction (Base Formula)

This is the base formula all other formulas are based upon. It is used to calculate the #% additional Physical Damage Reduction when Hit factor, i.e. the percentage by which the physical damage is mitigated.

$DR(A, D_{raw}) = {A \over A + 10 * D_{raw}}$

where A is the defender's armour rating and D_raw is the raw physical damage.

Required Armour Rating

To calculate the armour rating you need to mitigate a given amount of Physical Damage at specific ratio, you can use this formula:

$A(D_{raw}, DR) = {DR * 10 * D_{raw} \over 1 - DR}$

Reverse Physical Damage

You can also calculate the raw physical damage that would have resulted for a given Physical Damage Reduction and Armour rating:

$D_{raw}(A, DR) = {A \over 10 * DR} - {A \over 10}$

Resulting Physical Damage

To calculate the net physical damage (i.e. the damage after damage reduction, the following formula can be used:

$D_{net}(A, D_{raw}) = {10 * {D_{raw}}^2 \over A + 10 * D_{raw}}$

Absolute Physical Damage Reduction

Another way of looking at it is in terms of absolute physical damage reduction:

$DR_{abs}(A, D_{raw}) = {A * D_{raw} \over A + 10 * D_{raw}}$

Defense factor

$DF(A, D_{raw}) = {A \over 10 * D_{raw}} + 1$

examples

The plot below displays how much damage reduction occurs at different armour ratings and raw physical damage.

Armour reduction at varying armour ratings and raw physical damage

From the plot below we can further conclude:

• If raw damage is much less than Armour / 10, raw damage has a near-quadratic effect on net damage. Equivalently, in this regime raw damage has a near-linear effect on net DPS if the raw DPS is held constant.
• If raw damage is much greater than Armour / 10, raw damage has a near-linear effect on net damage. Equivalently, in this regime raw damage has little effect on net DPS if the raw DPS is held constant.
• Against attacks of a fixed raw damage, armour has a linear effect on the number of attacks it takes to deplete a certain amount of hit points.

Skills

The Determination aura increases armour of the character and nearby allies. The Molten Shell and Vaal Molten Shell skills temporarily grants player additional armour. The Summon Chaos Golem increase physical damage reduction, but not armour.

Unique jewels

The following jewels affect Armour:

Passive skills

There are passive skills that grant armour bonuses.

Armour rating

These passive skills grant increased armour rating or additional base armour rating. The Iron Reflexes keystone is special in that it converts evasion rating to armour rating.

Template:Passive table

Armour rating while Fortify

These passive skills grant increased armour rating while you have Fortify. Template:Passive table

Miscellany

These passive skills are related to armour, but do not fit into any other category.

Template:Passive table