Spell power

Spell power, prior to patch 3.0.2 known as spell damage and healing, is an attribute granted by buffs, talents, and equipment that increases the effect of spells. For damage spells, the amount of damage caused is increased, and for healing spells, the amount of healing is increased. Many items will increase damage from all magical schools as well as healing from all schools, while some items will only increase damage done by a particular school, or only increase healing. Each spell gets a fixed bonus that is determined by the spell type, casting time, target and/or way the spell is applied. Damage-dealing casters especially consider this attribute to be one of the most important attributes to attain.

Players often refer to this attribute as simply +damage, +dmg, or plus damage. For effects that target a specific school, it is similarly referred to by that school such as +fire. In particular, healers commonly refer to items with only a healing bonus as +healing.

Items with spell damage and healing have the following green "Equip:" text on the item, for example: "Equip: Increases spell power up 26." Alternatively, certain item suffixes can carry spell damage and healing - items with names ending in "of Fiery Wrath" or "of the Invoker" being two examples. These appear as white text on the item with the rest of the attributes. The effect of these items is equivalent to those with the green Equip: text, except they are spell specific.

Sources

Spell damage and healing is found primarily on equippable items, but can also be increased with potions, buffs and some class talents. Items with the following item suffixes will add spell damage or healing:

Suffix	Effect	Note
..of Arcane Wrath	+ Arcane damage
..of Fiery Wrath	+ Fire damage
..of Frozen Wrath	+ Frost damage
..of Healing	+ Healing spells
..of Nature's Wrath	+ Nature damage
..of Shadow Wrath	+ Shadow damage
..of Sorcery	+ Spell damage (not healing) + Stamina + Intellect	Found only on "Abyssal" items on summoned Silithus bosses.
..of the Crusade	+ Spell damage and healing + Defense rating + Intellect	Introduced in The Burning Crusade
..of the Hierophant	+ Healing + Stamina + Spirit	Introduced in The Burning Crusade
..of the Invoker	+ Spell damage and healing + Spell critical strike rating + Intellect	Introduced in The Burning Crusade
..of the Nightmare	+ Shadow damage + Stamina + Intellect	Introduced in The Burning Crusade
..of the Physician	+ Healing + Stamina + Intellect	Introduced in The Burning Crusade
..of the Prophet	+ Healing + Spirit + Intellect	Introduced in The Burning Crusade
..of the Sorcerer	+ Spell damage and healing + Stamina + Intellect	Introduced in The Burning Crusade

All spell damage and healing gains stack. The total bonus is determined by adding individual bonuses from all equipped items, all buffs, and any talents. The total amount of spell damage and healing can be tracked on the character sheet, under the Spell tab. Bonus Damage shows the total amount that applies to all schools. Mousing over Bonus Damage will break down the benefit by magical school, which includes items that only effect one school. Bonus Healing shows the amount that will be applied to healing spells.

Spell coefficients

The amount of the spell damage or healing bonus that is applied to the spell varies from spell to spell. This is called the spell damage coefficient, and it is mostly fixed for each spell. The coefficient can be determined by following some basic rules that are outlined in this section. It should be noted, however, that many exceptions to these rules exist, and the proper spell coefficient should be found experimentally.

Note: some calculations below end in a decimal result that should be less than 1. To get the % multiply that decimal by 100.

Different types of spells have their damage and healing bonuses calculated differently. There are three base types of spells: standard, over time or a combination. Area of Effect and Channeling spells also take different bonuses. After the proper bonus is calculated, penalties are calculated to achieve the final damage.

Standard spells

Standard spells are spells that apply all the damage or healing at one time. To determine the plus Healing or Damage benefit for these spells the following formula is used:

(Cast Time of Spell) / 3.5

Cast time	Coefficient	Cast time	Coefficient
7.0+ sec	200.0%	4.0 sec	114.3%
6.5 sec	185.7%	3.5 sec	100.0%
6.0 sec	171.4%	3.0 sec	85.71%
5.5 sec	157.1%	2.5 sec	71.43%
5.0 sec	142.9%	2.0 sec	57.14%
4.5 sec	128.6%	1.5- sec	42.86%

Instant spells are treated as 1.5 second cast time spells, with a coefficient of 42.86%

Spells with a cast time longer than 7.0 seconds are capped at 200%. The casting time used in the calculation should be the base cast time before effects from talents or gear are applied. Note that the tooltip in game includes those effects; refer to the article on a particular spell to get the base cast time.

Examples of such spells include: [Healing Touch] (Druid), [Greater Heal] (Priest), [Shadow Bolt] (Warlock)

Some exceptions of this rule are:

• [Soul Fire] (Warlock) - 115%
• [Pyroblast] direct damage: 115%, damage over time: 20%

Over-time spells

Over Time spells apply healing or damage over a period of time in ticks.

(Duration of Spell / 15) =  Total

Duration	Coefficient
3 sec	20%
6 sec	40%
9 sec	60%
12 sec	80%
15 sec	100%
18 sec	120%
21 sec	140%

Prior to patch 2.0.1, there was a 100% cap on over-time spells longer than 15 seconds. This cap has since been removed. The total bonus is divided equally to each tick.

Examples of these spells include: [Rejuvenation] (Druid), [Renew] (Priest)

Some exceptions to this rule are:

• [Shadow Word: Pain] (Priest) - 110%, increased beyond 140% with [Improved Shadow Word: Pain], which extends its duration to 24 sec.
• Corruption (Warlock) - 93%, can be increased to 129% with the talent [Empowered Corruption].
• [Curse of Agony] (Warlock) - 120%.
• [Curse of Doom] (Warlock) - 200%.

Hybrid spells (Combined standard and over-time spells)

The bonus for spells that have both a standard and an over time component is divided between them. The over time portion receives the following bonus:

(Duration / 15) / ((Duration / 15) + (Cast Time of Spell / 3.5)) = Portion to Over Time

The standard portion receives the rest:

1 - Portion to Over Time = Portion to Standard 

The duration and cast time limits are then applied:

(Cast Time of Spell / 3.5) * Portion to Standard = Total bonus to Standard Portion 

(Duration / 15) * Portion to Over Time = Total Bonus to Over Time Portion 

Examples of these spells include: [Moonfire] (Druid), [Immolate] (Warlock)

Exceptions to this rule include

• [Holy Fire] (Priest) - 85.71% (DD), 16.5% (DoT)
• [Regrowth] (Druid) - ~30% (DH), 70% (HoT)

Channeled spells

Channeled spells have their benefit distributed evenly over the time the spell is being cast, getting 100% benefit for the whole spell (not per tick). The duration of the spell cast time is used as with a standard spell to calculate the total benefit, then divided equally between the number of ticks.

Cast Time of Spell / 3.5 =  Benefit 

Examples of these spells include: [Hurricane] (Druid), [Arcane Missiles] (Mage), [Hellfire] (Warlock). An exception to this rule is:

• [Drain Soul] (Warlock) - 214.3%.

Area of effect spells

Area of Effect spells receive only 1/2 of the total bonus. The cast time is used as with a standard spell to calculate the total benefit, then divided by 2.

(Cast Time of Spell / 3.5) / 2 =  Benefit 

Cast time	Coefficient	Cast time	Coefficient
10 sec	142.86%	2.5 sec	35.71%
3.5 sec	50.00%	2.0 sec	28.57%
3.0 sec	42.86%	1.5 sec	21.42%

Examples of these spells include: [Tranquility] (Druid), [Arcane Explosion] (Mage), [Prayer of Healing] (Priest), [Hellfire] (Warlock)

Note that some spells fall under the rules for multiple spell types. Hurricane, Tranquility and Hellfire, for example, are all Area of Effect and Channeled. Prayer of Healing is both a Standard Spell as well as an Area of Effect spell.

In the Burning Crusade and patch 2.0 there is a diminishing return against multiple targets. That is, as the number of targets your spells affect increases, the less damage you will deal to them. The numbers for this mechanic aren't yet known.

Paladin special attacks

Some Paladin abilities work different ways. Here are some formulas tested in beta version of the Burning Crusade.

[Holy Shield], [Retribution Aura] (Paladin) reflects damage:

5% of +spell damage effect = +damage applied for each charge

Only Paladin aura benefit from +dmg. A Druid's Thorns spell doesn't get its damage increased except by the Brambles talent.

[Seal of Righteousness], which applies holy damage on each melee attack:

One-handed weapons:

9.2% * Weapon Speed in seconds = Total

1.0 sec = 9.2%
2.2 sec = 20%
 

Two-handed weapons:

10.8% * Weapon Speed in seconds = Total

2.6 sec = 28%
3.7 sec = 40%

Rules for applying spell damage and healing

1. Calculate spell time using the base spell cast time before talents and gear. (The in-game tool tip will include those bonuses; refer to WoWWiki's spells section for base cast times for all spells.)
2. Spells that take longer than 7.0 seconds to cast are treated as if their casting time was 7.0 seconds, and spells faster than 1.5 sec are treated as if their casting time was 1.5 seconds.
3. Damage benefits are applied before any talents or buffs that may otherwise increase your spell damage.

Penalty rules

Spells learned before level 20

Many spells have multiple ranks. To avoid abuse of lower ranks to have a similar effect at a negligible mana cost, any spell learned below level 20 receives a large penalty. If such a spell has a shorter cast time than a higher rank, this is also taken in to account. This penalty can be calculated by subtracting 3.75% for each level lower than 20.

(20 - Level Spell is Learned) * .0375 = Penalty

Downranked spells

Main article: Downranking

Downranking, the act of purposefuly using a lower-rank cheaper spell, is no longer possible as of patch 3.0.

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Spells with additional effects

Spells with additional effects, like a slowing effect, get a 5% penalty to damage and healing bonuses. This penalty is applied after the spell type calculation, before other penalties. For example, a standard area of effect spell with an slow effect would be calculated like so:

((Cast Time of Spell / 3.5 ) * .95 Penalty for extra effect) / 3 = Benefit 

Examples of these spells include: [Blast Wave] (Mage), [Blizzard] (Mage)

The above calculations are for Area of Effect spells with a snare, identified by the " / 3" at the end. For single-target spells, use the following formula:

((Cast Time of Spell / 3.5 ) * .95 Penalty for extra effect)= Benefit 

Examples of these spells include: [Entangling Roots] (Druid), [Frostbolt] (Mage)

Note that in patch 2.1, multiplier for additional effect has changed a lot. For some spells the multiplier is still 0.95, while it might be quite different in many other cases. Here's a list for some of the AoE spells.

Flame Strike DD：23.6% (417/757 * 3/3.5 * 1/2)
Flame Strike DOT：9.9% (340/757 * 8/15 * 1/2 * 0.83)
Blast Wave：19.3% (1.5/3.5 * 1/2 * 0.9－special effect)
Dragon Breath：19.3% (1.5/3.5 * 1/2 * 0.9－special effect)
Molten Armor：0％
Blizzard：95% (8/3.5 * 1/2 * 0.83)
Cone of Cold：19.3% (1.5/3.5 * 1/2 * 0.95－slow effect)
Frost Nova：2.8% (1.5/3.5*1/2*0.13－special effect)
Ice Barrier：10％ (given constant)
Ice Lance：14.2％ (1.5/3.5 * 1/3－ triple dmg on frozen target)

Spells that both damage and heal

Some spells, namely Life Drains, both damage the target and heal the caster. These spells have a 50% penalty to the bonus they receive, but bonuses to spell damage increase both the damage and the healing of the spell equally. These spells receive no bonus from effects that only increase healing.

Examples of these spells include: [Devouring Plague] (Priest), [Drain Life] (Warlock)

Exceptions

• Corruption (93%), [Curse of Agony] (120%), [Curse of Doom] (200%) and [Shadow Word: Pain] (110%) receive a reduced bonus.
• [Drain Soul] has its bonus reduced to half (214%).
• [Fireball] has a small damage over time component, but is not considered a hybrid spell, so it receives only the Direct Damage bonus to its direct damage component. Spell damage gear never increases the DoT on fireball.
• [Holy Fire] does not follow hybrid spell rules and receives 85.71% (DD) and 16.5% (DoT).
• [Mind Flay] does not follow channeling rules and uses 57% damage applied.
• [Soul Fire] is capped at 115%.
• [Power Word: Shield] does not follow instant cast rules and applies 30% of bonus healing.
• [Pyroblast] deals 115% of +spell damage on impact and 20% of +spell damage to its DoT component.

Additional notes

1. +Healing does not apply to bandages or potions. Trinkets should no longer be affected.
2. Shaman totems receive benefit from +Damage.
3. Hunter Traps don't receive a benefit from increased spell damage.

See also

• Spell Damage Coefficients
• Spell Damage Comparison