Each item in WoW has a certain power. Its power is determined by its slot, its rarity and its ilvl. The slot and rarity of each item are visible in the game. The ilvl is something that is not shown but it represents how powerful that item is in the specific slot and rarity. For example not all epics are equal. An epic form heroic raid dungeons is 13 item levels higher than epics from normal raid dungeons and as such it is quite a bit more powerful.
|Item budget||The sum of the stats of an item. See Item Level for more information|
|Item level or short ilvl||The item level of an item is what determines its item budget in the same rarity and slot|
|Slot or item slot||The slot in which the item can be equipped|
|Rarity||The rarity of an item. Examples are uncommon, rare, epic, legendary|
|Tier||A loot tier. Molten Core was Tier 1, Blackwing Lair Tier 2, and so on|
|Class||The class of a toon: Warrior, Priest, Rogue, and so on|
|Spec||The spec a class plays: Protection, Arms, Fury, Restoration, and so on|
|White stats||The inherent stats of an item which do not depend on choices of Blizzard's itemization. These are: armor of an item, white dps on a weapon|
|Green stats||All the stats that are not white stats on an item|
When designing the GP formula the following requirements were set:
- Total GP for each class/spec should be ideally the same.
- Items of a whole new and better tier should be increasingly more expensive. A factor of two was chosen for each tier.
- Each item should cost as much GP as it's power according to the class/spec that uses it.
While the relative item budget between slots is widely known (Item Level) there are class/spec combinations for which an item is more beneficial than others. These depend on how the class/spec is designed and what kind of stats it prefers or primarily uses. The cases we are more interested in are:
- Shields: A tanking shield is used by shield capable tanking classes. In that case a tank is interested in both the white stats and the green stats of an item. A healing shield, which is used by shield capable healers, is used primarily, if not exlusively, for its green stats. This should be taken into account by the GP formula.
- Weapons: Melee classes use both the green and white stats of a weapon. Both the dps of the weapon and the stats on it are useful. The white stats of a weapon are not at all useful for a hunter. This also needs to be taken into consideration. Note: Casters get the white dps of a weapon and make it into spell power through some fixed formulas, so spell power on weapons is considered a white stat.
- Ranged weapons: Hunters use ranged weapons for both their white stats and the green stats. This is not true for melee classes which use these items only for their green stats.
- Off-hand weapons: These weapons are used by dual wielding classes/specs and because of the off hand weapons 50% damage modifier, the white stats on these items are severely less important. Obviously GP needs to account for this as well.
With the above in mind the following formula was devised:
GP = 0.483 x 2 ilvl/26 + (rarity - 4) x slot mod
Rarity is given by this table:
Slot modifiers depend on the slot each item can be equipped. In addition to that, the forementioned differences between the use of certain weapons/offhands is taken into consideration. This means some items have two possible GP values which depending on who uses them and how they are used.
The basic values slot modifiers for each slot are:
|Head, Chest, Legs, 2H weapon||1|
|Shoulder, Hands, Waist, Feet, Trinket||0.75|
|Wrist, Neck, Back, Finger, Off-hand, Shield, Wand, Ranged Weapon||0.5|
Under certain circumstances a different modifier is used. These are:
- 2H Weapon:
- If it is going to be used as an offhand (TG warriors for example) the modifier becomes 1 (down from 2)
- If it is going to be used by a hunter the modifier becomes 1 (down from 2)
- 1H Weapon:
- If it is going to be used by a hunter the modifier becomes 0.5 (down from 1.5)
- If it is going to be used by a tank for tanking purposes the modifier becomes 0.5 (down from 1.5)
- If it is going to be used as an off-hand the modifier becomes 0.5 (down from 1.5)
- If it is going to be used by a tank for tanking purposes the modifier becomes 1.5 (up from 0.5)
- If it is going to be used by a hunter the modifier becomes 1.5 (up from 0.5)
This gives more or less equal GP value for MH + OH + Ranged slots for all classes:
|Tank with shield||0.5||1.5||0.5||2.5|
|Caster with shield||1.5||0.5||0.5||2.5|
As shown by the table most classes end up with the same totals, with the exception of TG warriors that are charged a little bit extra.
With the theory out of the way lets see some examples of items and how different components of the equation affect GP.
A tier of gear difference. Both items are epic 2H weapons, but they have a whole tier of loot difference:
As expected the higher tier item is 2x as much GP as the lower tier one. Now lets see two items of the same ilvl, same slot but different rarity:
Again as expected the two items have a 2x GP difference between the two weapons because the one is epic and the other one is rare. With the rarity and tiers out of the equation lets look at the whole tier 7.10 set for the warrior class:
- Heroes' Dreadnaught Helmet 99 GP
- Heroes' Dreadnaught Battleplate 99 GP
- Heroes' Dreadnaught Legplates 99 GP
- Heroes' Dreadnaught Shoulderplates 74 GP
- Heroes' Dreadnaught Gauntlets 74 GP
As you can see both shoulders and hands are 0.75x of the cost of the head, chest and leg items since their relative power is 0.75x as much.