Hit

Hit refers to physical damage that occurs as a result of an attack made with melee or ranged weapons. The chance to hit increases by 1% per 30.7548 points of hit rating at level 80, 14.7905 hit rating at level 70, and 9.3793 hit rating at level 60. The base chance to miss against an opponent of equal level is 5% for single wield and 24% for dual wield. Both hit and spell hit use the same basic hit rating attribute within the combat rating system, although the similarity largely ends there—they are effectively distinct attributes derived from the same rating.

Calculating Miss Rate
If the difference between the mob's level and your level is less than or equal to 2, then the formula for calculating your base miss rate against that mob is:


 * with single-wielding: 5% + (Mob Level - Your Level) * 0.5%
 * with dual-wielding: 24% + (Mob Level - Your Level) * 0.5%

If the difference between the mob's level and your level is greater than 2, then the formula for calculating your base miss rate against that mob is:


 * with single-wielding: 2% + (Mob Level - Your Level) * 2%
 * with dual-wielding: 21% + (Mob Level - Your Level) * 2%

Applying these formulas gives the following base miss rate for a Level 80 character:


 * v. Level 80 mob: 5.0% / dual-wield: 24%
 * v. Level 81 mob: 5.5% / dual-wield: 24.5%
 * v. Level 82 mob: 6.0% / dual-wield: 25% (level of most heroic bosses)
 * v. Level 83 mob: 8.0% / dual-wield: 27% (level of raid bosses)


 * 30.75 hit rating reduces your chance to miss by 1%

Thus, if you are a Level 80 character with no talents increasing your chance to hit, you need a Hit Rating of 247 (8.03%) to never miss a shot against a Level 83 boss (or skull mob) with a special attack or single-wield auto-attack (see hit rating cap below).

Melee attacks divide into two categories: auto-attacks (white attack/damage) and special attacks (yellow attack/damage). Attacking a mob from behind removes parry and block from both tables, provided the attack is more than 0.5 yards away (measured from center to center rather than with the hitbox).

Hit rating cap
In the context of stats, the term "cap" refers to the point at which equipping more of a particular stat will have no additional value. For hit rating the cap usually discussed is in regards to raid bosses. For example, once you reach or surpass the hit cap, you will never miss an attack against a raid boss unless you are under the effect of some debuff that reduces your hit chance (for example, Archavon the Stone Watcher's gas cloud).

As shown above, your base chance to miss a raid boss while dual wielding is 27% with auto-attack on both hands. Your base chance to miss a special attack is 8%. For each 14.79 hit rating at level 70 or 30.75 hit rating at level 80, you reduce your chance to miss by 1%. Thus we can calculate hit caps for auto-attack and special attacks:

A "soft" cap is the point at which your yellow attacks will always hit and more hit rating has no effect on them. A "hard" cap is the point at which your autoattacks will always hit and more hit rating does absolutely nothing for you.


 * Note: For DPS exclusively doing heroics and not planning on raiding at all, the hit cap is lower, since heroic bosses are never higher than 82 (see "Calculating Miss Rate", above).

All level 85 physical DPS

 * Dual-wield auto-attack: 3 243 hit rating
 * Special DW attack or any type of Single-wield attack (auto/special) or any type of ranged physical attack (auto/special): 961 hit rating

Hit rating chart
Note: for practical purpose, since hit rating is always integer, you need to round up the above numbers to ensure true hit-cap.

Heroic Presence
Heroic Presence is a draenei passive ability that gives that draenei a 1% reduction in hit rating requirement.

Auto attacks
Each melee auto attack made by characters against mobs will result in one of the following (in order of precedence):

Hit chance doesn't work by increasing the amount of "Hit" on these tables. Instead, it works by decreasing the amount of miss.

Critical strike chance "fills in" the hit chance portion of this table. Crit is "capped" when the crit chance exceeds the amount of hit chance on the table. Until we reach that cap, hit chance has NO effect on crit chance. For example: maximum dual wielding weapon skill, chance to hit 0% and chance to critical strike 50%. Dual wield auto-attacking a raid boss from behind results in a loss of 8.6% critical strike:
 * Example #1

Increase chance to hit to 10% and decrease chance to critical strike to 45% results in no loss of critical strike:
 * Example #2

It is actually quite difficult to be crit capped without trying. This is one reason why it's important to maintain a balance of stats, and not to "stack" any one stat indiscriminately.

Special attacks
Each melee special attack made by characters against mobs will result in one of the following (in order of precedence):

The system is exactly the same as normal attacks, except the miss chance is reduced to 8%, whether dual-wielding or not.

Enchantments

 * - Ranged only.
 * Enchant Weapon - Accuracy
 * Enchant Gloves - Precision
 * Enchant Gloves - Precise Strikes - Enchant learned from.
 * Enchant Boots - Icewalker
 * Enchant Boots - Surefooted
 * Enchant Boots - Lesser Accuracy - Added in patch 3.1.
 * Enchant Boots - Icewalker
 * Enchant Boots - Surefooted
 * Enchant Boots - Lesser Accuracy - Added in patch 3.1.
 * Enchant Boots - Lesser Accuracy - Added in patch 3.1.
 * Enchant Boots - Lesser Accuracy - Added in patch 3.1.

Cooking
adds 20 Hit rating for 30 minutes.

and add 40 Hit rating for 1 hour.

Common misunderstandings
Some players ignore hit, when hit rating is the most valuable stat for most DPS classes. This is because for the same amount of item points, hit rating usually gives a higher increase in overall damage output than other stats. Therefore, it is advisable for most DPS to stack hit rating until hit-capped.

It is also common to see people over-value the benefit of hit rating. Some players stack hit rating indiscriminately without realizing that their hit is over-capped by a large amount. Any hit rating above the hit cap is useless. One should adjust the hit rating so that they are not over the cap by too much.

Another common misconception is that some people over value hit rating, to such an extent that they choose gear of a lower quality with hit rating over other gear that has a higher quality but no hit rating. They forget why one wants hit rating: to maximize the damage output. For example, imagine there are two helms with similar stats except that one has 20 more hit rating, while the other has 40 more critical strike rating (or other stats for classes that value crit less). Although 1 hit rating is better than 1 critical strike rating usually, 40 critical strike rating can be better than 20 hit rating. Therefore, one should still choose the second helm even this means he/she will be further away from being hit-capped. In general, we should choose the piece of gear that provides higher improvement in damage output, regardless of whether it has hit rating or not.

Another point some raiders do not consider is that many fights in ICC are 'adds' fights. The spell hit rating requirement for a level 83 raid boss is 17%. For a level 82 add, it is 6%. Assuming the Gunship adds, Saurfang blood beasts, and Dreamwalker adds are level 82s, it can be said that many casters are over hit for those fights. Each raider should decide if killing the adds is more important than dpsing a raid boss, and what amount of hit rating gives the raid the most benefit. Gear can be swapped on a boss by boss basis. One set can have 17% hit, and the other set can drop hit for something contributing to higher dps. Maghia's Misguided Quill can be used for bosses but swapped out for 'adds' fights.