Mana is a magical power resource available to casters which they draw upon when casting spells. It has some parallels with other "bar"-type resources, but unlike the others is consumed relatively slowly. The amount of mana currently available to the caster is denoted with a special blue mana bar below their health bar. By default, casters start with a full bar of mana which is then depleted as they cast spells.
Characters have an innate replenishment of both health and mana. Some passive abilities can raise the replenishment rate for these stats independently. During combat mana regeneration is reduced, but some mana can be replenished instantly during combat using mana potions from alchemists or from various magical items. Out of combat, mana regeneration can be increased significantly by using various drinks. Mana regeneration can also be increased through the use of certain buffs.
Since Patch 5.0.4, the maximum amount of mana available to a caster is determined by their spec and level, although certain modifiers such as can increase it by a small amount.
Prior to Mists of Pandaria the maximum amount of mana available to a caster was determined by a combination of the character's class and their level. Prior to Legion, the Spirit attribute affected rate at which mana replenished (mana regeneration).
Base mana is a term used to refer how much mana a character has before it is modified by other effects. Many spells require a percentage of your base mana to be cast. Mana pool refers to the total amount of mana a player possesses, disregarding any increasing or decreasing effects (though it usually refers to the sum of increasing). "Mana pool" should not be confused with "mana pooling", a relatively rare resource management strategy.
Base mana and mana pool
Different specialisations have different relationships between base mana and their actual mana pool. While a character's mana pool is fixed by their level, it can be either equal to their base mana, or 5 times the base mana (400% greater than base). This affects the interpretation of spell costs, which are usually quoted as a percentage of base mana, not necessarily mana pool. The cost of abilities for hybrid classes should be divided by 5 to convert them from a percentage of base mana, to a percentage of mana pool. As an example, the Shaman's and Priest's have a similar purpose. However, Healing Wave's cost is listed as 9% of base mana. As a real percentage of mana pool, 9/5 is 1.8%, much closer to the value of 1.85% for Heal.
- Melee/Caster hybrid classes in a melee specialization have the same Base mana and Mana pool. At level 90, this is 60K mana. These specializations include Feral and Guardian Druids, Protection and Retribution Paladins, and Enhancement Shaman.
- Melee/Caster hybrid classes in a caster specialization have a Mana pool that's 5 times greater than their base mana. At level 90 this is 5 X 60K = 300K mana. These specializations include Balance and Restoration Druids, Holy Paladins, and Elemental and Restoration Shaman. These specialization have passive abilities like , , (for restoration shaman) and (for elemental shaman) that "multiply" their mana pools.
- Pure Caster classes also have the same Base mana and Mana pool. However their Base mana is inherently 5 times greater than that of a Melee/Caster hybrid, giving them a Base mana and Mana pool of 300K mana. These classes include Mages, Monks, Priests and Warlocks. Although Monks are an example of Melee/Caster hybrid classes, they only have access to mana in their spell-casting specialization i.e. Mistweaver. So they have no need of "mana multipliers" like the other hybrid classes and thus have the same Base mana and Mana pool.
- Patch 6.0.2 (2014-10-14): Maximum mana has been doubled at all levels to keep pace with expected increases to maximum health from new Stamina values.
- Patch 5.0.4 (2012-08-28): Mana is no longer affected by Intellect.
- Patch 3.0.2 (2008-10-14): Mana and no longer uses the "tick" system and instead regenerates in real time.