Cooldown is a property of some powers in Diablo III and subsequent games, primarily character skills, which prevents it from being activated again until a set time has passed. The concept was first introduced as Casting Delay in Diablo II, but that system did not interact with any other game mechanics. Certain item powers and Monster Skills also have cooldowns.
Cooldown Reduction (CDR) is a percentage-based character stat which reduces the length of skill cooldowns, available from many sources. It is an important stat for some builds, allowing more frequent or even continuous use of some skills.
Skills[]
Active skills with cooldowns start a timer when used (a few instead start the timer after their effects end), as do charge-based skills that are not already recharging. Until the timer expires, attempting to re-use a cooldown skill simply does nothing; the same is true for skills with no charges remaining. The skill is said to be "on cooldown" during this time. For charge-based skills (e.g. Dashing Strike or Revenge), when the timer expires for one recharge period, a charge is restored, and the next recharge period begins immediately if the maximum has not been reached. Recharging benefits fully from Cooldown Reduction.
Cooldown time is visually indicated by a pie chart / clock-style shaded area on the skill icon in the action bar. When a skill is used, the icon becomes fully gray, indicating the cooldown has just begun. Then an increasingly large angle becomes uncovered as time passes, progressing clockwise. The shading turns from gray to orange as the cooldown approaches completion. When it finishes or is reset, the button briefly flashes to indicate the skill is ready for use again. Longer cooldowns move slowly through the 360 degree rotation, while short ones move quickly.
Cooldown skills range from short-cooldown utilities to attacks with a massive impact on the battlefield that may serve as centerpieces or "finishing moves" to a fight. Some have cooldowns of just a few seconds, while the most powerful may go up to 60, 90, 120, or even 180 seconds. Cooldowns longer than that are very rare.
Cooldowns are one of two major limitations skills may be designed with to avoid them being over- or underpowered; the other is its resource cost. Some skills have both limitations, while others such as Diablo III Primary Skills have neither, and can therefore be used as much as Attack Speed allows, but have correspondingly low power.
Some skills have durations of effect. Those that strongly empower the character, such as Archon or Wrath of the Berserker, are designed with cooldown timers longer than durations. This means the character cannot be empowered all the time by re-using the skill before the duration expires by default, but this is possible with high enough Cooldown Reduction. On the other hand, some skills instead do not start cooling down until their effects have ended, generally skills that grant immunity to damage, like Serenity or Falling Sword, or make it difficult to be targeted by enemies, like Smoke Screen or Spirit Walk. This prevents characters from achieving permanent immunity with high Cooldown Reduction - they must always wait some time before the the effect can be reused.
Skills like Unstable Anomaly, which trigger automatically and have exploitable effects like cancelling death, are designed with hard limits to how frequently they can take effect. While the concept is similar to other cooldowns, such skills do not use regular cooldown mechanics, and do not benefit from Cooldown Reduction or other interactions. They usually show a debuff icon on the screen after they have activated. Only death cancels this restriction.
Follower active skills all have cooldowns (and do not use resources). However, none of them benefit from normal Cooldown Reduction, with the exception of Kormac's Heal skill. The AI will generally use the skills shortly after they are off cooldown, if appropriate for the current circumstances.
Mechanics[]
Cooldown management is a vital part of gameplay, although some cooldown-independent builds exist as well.
There are two quantities involved when using a cooldown skill, both of which can be updated by effects during combat:
- The skill's overall cooldown time, which is determined by taking the base cooldown of the Skill Rune (occasionally modified by flat reductions from other sources), and reducing that by any percentage-based cooldown effects, most notably the character's current Cooldown Reduction stat. Changes to this value, such as by gaining or losing Cooldown Reduction, are not obvious visually, since the icon always starts fully gray regardless of cooldown length, but the progress indicator will move more quickly the lower the overall cooldown time is.
- The current time remaining on the cooldown period, which generally starts equal to overall cooldown and decreases with the natural passage of time. Thus, if no other effects are involved, the actual duration the skill is on cooldown is equal to its overall cooldown time at the moment the skill was activated. Special powers that decrease the current cooldown's time create an abrupt jump in the progress of the rotating cooldown indicator, although this can be harder to notice for long cooldowns.
A skill cannot be replaced by another in the action bar while it is cooling down, preventing rotation through multiple high-cooldown skills in a single action bar slot. All cooldowns are reset immediately when a Greater Rift is started.
Cooldowns continue to recharge even while a character is dead.
Interactions[]
- See also: List of cooldown modifiers (Diablo III)
Many effects and character statistics can change skill cooldown times. These changes are not accounted for in the Damage, Toughness, and Recovery "estimated stats" on the Diablo III Character Screen, but they can have a huge impact nonetheless.
Each skill has a set base cooldown time, possibly 0. Some Skill Runes change this base, remove the cooldown entirely (often adding a resource cost in its place), or add one that was not present in the un-runed version. Certain Legendary Item unique powers and a few passive skills make similar changes. All further interactions are relative to this base cooldown period.
Most non-rune cooldown modifiers affect either the overall cooldown time or current time remaining of one or all skills, as described in the section above. Most of them are locked in during combat, but some changes in these values can occur while adventuring.
- Naturally, if the current time remaining is reduced by a special power, it does not affect the overall cooldown period; the next use of the skill still starts back at the full duration. For example, a 10 second cooldown may have 2 seconds removed from its time by killing enemies with Messerschmidt's Reaver while cooling down, and became available again only 8 seconds after its previous use. It will still take 10 seconds to cooldown on its next use, assuming no further reductions.
- More surprising is the converse: If the overall cooldown time is modified while the skill is already on cooldown, the current time remaining is not modified - even if the new overall cooldown time is less than the current time remaining! For example, a player with no stacks from Gogok of Swiftness may use a 120 second cooldown and then gain 15 stacks from the Gogok over the next 10 seconds, granting 15% Cooldown Reduction. The current time remaining on the long cooldown would then be 110 seconds, while the overall cooldown time for the skill would only be 120 * .85 = 102 seconds. If the Gogok stacks are maintained, the next use of the skill would take 102 seconds to cool down, but the current period would still last 120 seconds total.
Cooldown Reduction[]
Foremost among modifications is Cooldown Reduction (CDR), a percentage that is removed from the overall cooldown time of all skills. This stat is the only cooldown modifier listed as an explicit secondary stat in the Character Screen. It is categorized under "Offense", although many defensive skills benefit from CDR as well. CDR applies the moment a skill is activated, so subsequent changes to the stat have no effect on a skill that has already started cooling down.
Cooldown Reduction can appear as a random primary magic property on items, stated as "Reduces cooldown of all skills by X%". For maximum level Legendary Items, it can appear in the 6-10% range on any weapon, and 5-8% on gloves, pauldrons, rings, amulets, and off-hand items including shields. Ancient Items have the same ranges.
CDR can also be granted by Diamonds socketed into helms, Paragon points, Shrines, passive skills, unique Legendary Item powers, and item set bonuses.
Multiple sources of Cooldown Reduction apply sequentially. For example, a 20% CDR passive results in a cooldown length 80% of the original. If a 10% CDR item is also equipped, it reduces 10% of that 80% (8% of the original cooldown time), resulting in a final cooldown time 72% as long as the original. This can also be thought of as multiplicative stacking of CDR effects, if they are stated in terms of the relative remaining cooldown times: .8 * .9 = .72, with the same example. Note that regardless of the order of the effects or how many there are, the result will be the same. This is a form of diminishing returns for Cooldown Reduction (e.g. a new source is only half as effective if the character already has 50% CDR), and it is impossible to achieve 100% CDR through combinations of smaller effects.
There are some builds focusing on keeping lower cooldowns for long-recharging spells, but the cap for most classes is around 72-75% (84.5-88.5% with Leoric's Crown).
Aside from the normal benefits of Cooldown Reduction, Captain Crimson's Trimmings also grants a direct bonus to damage equal to a character's Cooldown Reduction stat.
Followers, items and passives[]
Generally, cooldown modifying effects do not apply to anything but active skills used directly by player characters. This rules out:
- Followers benefitting from CDR on their equipped items, with the exception of Kormac's Heal skill.
- Each follower does have a Legendary trinket that halves their skills' cooldowns: Vadim's Surge, Slipka's Letter Opener, and Hillenbrand's Training Sword.
- Internal cooldowns of items with effects that trigger automatically.
- Passive skills that "can only trigger once per [period]", most notably the "savior" skills like Nerves of Steel. This also applies to similar effects like the Firebird's Finery 2-piece bonus.
- The potion cooldown of 30 seconds.
- The only ability in game able to reduce this is the Blood Flask Necromancer skill rune.
Some special powers may trigger an active skill of a player character. If the player also has that skill in their action bar, its cooldown is usually separate from the specially-triggered one.
See also[]
- Internal cooldown - Cooldowns for special item powers that trigger automatically. These are usually "hidden" and cannot be controlled or interacted with.