This guide is based on the original guide from the official website. Please enhance and add things you think are missing!
Item Power, often shortened to IP, is a value assigned to gear pieces, such as armor, weapons and accessories, to measure their strength. An increase in item power will improve most (all?) of an item's flat bonuses, though percentage bonuses are unaffected. The magnitude of this increase is described a bit in this forum post by Korn.
Average Item Power
The average item power is the calculated average of all of the IP of your gear. This number is purely for reference as raising the average does not necessarily mean that a certain aspect such as damage is higher. In order to increase damage for example, you would need to directly increase the IP of the weapon you are using, even though adding more IP to armor could raise the average IP. Items taken into account when calculating Average IP are:
- Head gear
- Chest gear
- Main hand
- Off hand (if applicable)
- Cape or pack
Note that the satchel slot does not count towards Average IP. To view your average IP you can open your inventory and click the details button. See gallery for example. To see average IP of other players, you can inspect them. To do so right click the player or if targeted, right click their portrait and select inspect. See gallery for example window.
Determining Item Power
There are 2 types of gear: normal gear, which doesn't need any special item for crafting; and artifact gear, which needs either a rune, soul, relic, or avalon artifact to be crafted. Each artifact level adds 25 IP.
There are 8 tiers of gear. Each tier above T4 adds 100 IP.
There are 3 types of enchantments: uncommon, rare, and exceptional, which are often known as .1, .2, and .3, respectively. Each enchantment level adds 100 IP.
There are 5 different item qualities and each gives a higher bonus to the overall IP:
|Quality||Item Power Bonus|
Mastery Modifiers grant an additional percentage to you IP for items T5 up to T8.
This encourages use of higher tier items when you have obtained specialization in them.
e.g. +100 IP from 50/100 specialization while using a T4 item vs +120 IP while using the same T8 item.