Resilience

Resilience is the bread and butter PvP stat. Resilience is a character attribute that reduces damage taken from players.

Characters have no innate resilience. It can only be gained through external sources, e.g. equipment, elixirs, enchantments, gems, and some spell effects that grant resilience rating. Many items and recipes that grant resilience rating are PvP rewards.

Resilience was introduced with World of Warcraft: The Burning Crusade as part of the new combat rating system. Previously, no such resilience mechanic existed — as a result, resilience rating only appears on items available to players over level 60, with some rare exceptions.

As of Patch 4.0.1, resilience no longer reduces the chance to receive a critical strike. Prior to that patch, 1% resilience would've given a player 1% less chance to be critically struck.

Formulas
One percent of resilience has the following effects:
 * Damage taken from all player attacks is reduced by 1%.

As part of the combat rating system, the amount of resilience rating needed to get a certain amount of resilience increases with level. A higher level player will need more resilience rating to get the same effect as a lower level player. At level 85, a player need 95.22 resilience rating to get 1% of resilience.

Resilience only reduces overall damage taken from players - the reduction has no effect on the damage of mobs.

Resilience rating required per 1%


Levels 60 through 70 use the following formula: Rating for 1% resilience = 2050/(262-(3* Level))

Levels 8 through 60 use the following formula: Rating for 1% resilience = (Level - 60) * (0.48) + 25

These two formulas result in the chart below:

(Note: Chart has been updated for 3.2.0) ''Information from http://elitistjerks.com/f31/t29453-combat_ratings_level_80_a/. Ratings 46 and below are inaccurate, but close ''

For any given level, divide your rating by the factor in the chart.

For example, total resilience rating on items is 20 at level 39 it would equal 1.34 % resilience. 20 / 14.92 = 1.34 % resilience.

It's a straight multiplication if you wanted to know what rating you needed at any given level for any amount of resilience. There are no diminishing returns on resilience. Doubling the rating doubles the effect for any given level. Tripling the rating triples the %, etc. For example, if you wanted to know what rating you needed at level 52 for 4.7% resilience, multiply (21.14 * 4.7) = 99.45 rating. 0.45 not rating is possible because rating is in whole numbers. You always have to round up. For a minimum of 4.7% resilience at Level 52 you would need a 100 rating.

PvP Sample
This is a sample of how resilience works in real PvP. The target suffers 8k direct damage (with 10/20/30/40% critical chance) and more 2k from dot.(8k+2k=10k damage but the deflection is critical chance for the 8k)
 * green&rarr; 7272,7272 (normal) with 10% critical chance + 2000 (dot) = max 10k Damage 
 * purple&rarr; 6666,6666 (normal) with 20% critical chance + 2000 (dot) = max 10k Damage 
 * yellow&rarr; 6153,8461 (normal) with 30% critical chance + 2000 (dot) = max 10k Damage 
 * blue&rarr; 5714,2857 (normal) with 40% critical chance + 2000 (dot) = max 10k Damage 

Calculation base:1414.5 resilience → 33% critical damage reduction  If we have a great rate (800+), we have major protection against players with high critical chance. This diagram shows the cap and the another border where the line fault (crit% 0). We can see all 4 curves are hooked till the crit chance become 0 or reach the cap. After that they are linear. More resilience is more protection but it is rarely linear!!!
 * 1 resilience: critical chance reduction and dot reduction: 0,010608204
 * 1 resilience: critical damage reduction and manadrain reduction: 0,023338048

Resilience cap
3.3.3 is the current patch at the moment this is written. The damage reduction from a critical strike is capped at 33%, which equates to 1414,5 resilience (94.3*33/2.2) at level 80 . This reduces your crit damage taken by 33% (the max allowed). It's a soft cap because there is no limit on your ability to reduce another player's % chance to crit against you (other than they can't go below 0%). The cap is just on the damage reduction of the crit. )

Many believe that the current Resilience cap is 1230 (82*30/2), but that was the old Resilience cap before Patch 3.0.3

before 3.2.0 a player needed 82.0 resilience rating to get 1% resilience at level 80.

after.. 3.2.0 a player needed 94.3 resilience rating to get 1% resilience at level 80.

before 3.0.3 the maximum damage reduction to a critical strike from resilience was 30%.

after.. 3.0.3 the maximum damage reduction to a critical strike from resilience is 33%.

before 3.0.3 The damage reduction component of resilience was 2 times the critical strike chance reduction.

after 3.0.3 The damage reduction component of resilience is 2.2 times the critical strike chance reduction.

Old 82*30/2 = 1230

New 94,3*33/2.2 = 1414,5

Enhancements
Leg Slot
 * Permanently adds 28 stamina and 40 resilience rating to a leg slot item.

Head Slot
 * Permanently adds 30 stamina and 25 resilience rating to a head slot item.
 * Permanently adds 29 spell power and 20 resilience rating to a head slot item.
 * Permanently adds 50 attack power and 20 resilience rating to a head slot item.
 * Permanently adds 18 Stamina and 20 resilience rating to a head slot item.

Shoulder Slot
 * Permanently adds 30 Stamina and 15 resilience rating to a shoulder slot item.
 * Permanently adds 23 spell power and 15 resilience rating to a shoulder slot item.
 * Permanently adds 40 attack power and 15 resilience rating to a shoulder slot item.

Elixirs

 * Increases Resilience Rating by 30 for 60 min.

Flasks

 * Increases Resilience Rating by 50 for 60 min.

Enchantments
Chest Enchants
 * Enchant Chest - Exceptional Resilience: Permanently enchant chest armor to increase resilience rating by 20.
 * Enchant Chest - Major Resilience: Permanently enchant a piece of chest armor to grant 15 resilience rating.

Shield Enchants
 * Enchant Shield - Resilience: Permanently enchant a shield to grant 12 resilience rating.