Item Level

Item Level or iLvl of gear determines that gear's quality. Gear with a higher iLvl will nearly always be better than gear with a lower iLvl.

Player characters have an average item level that is the sum of the ilvl of all the equipped pieces of gear divided by the number of slots. Unless the player's is equipped with a Shield, the main hand weapon's ilvl is counted twice in place of the empty off-hand. Thus, when trying to reach a required minimum item level for a duty, it can be best to upgrade the weapon first, even for tank or healer classes.

A notable caveat is with craftable gear. Only High Quality gear has appropriate stats for its Item Level. Any (NQ) Normal Quality gear has a 10% penalty in ilvl versus Dungeon or Tomestone rarity gear