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Attack Speed Mechanics

Last Updated: May 21st 2024

Season 4 - Loot

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Understanding Attack Speed Mechanics in Diablo 4 allows you to maximize your damage output and make educated decisions regarding your stat choices. This article aims to explain the core functionality of Attack Speed and how to make the most out of the stat.

Attack Speed

Attack speed in Diablo 4 makes your character attack faster, and how fast you attack depends on two factors. The first is Attack Speed% (henceforth AS%) sources from stats, items, paragons, aspects, etc, and the second is the Attacks per Second (henceforth ApS) of your weapon. These two factors have finite caps, meaning we have a finite max ApS that is reachable. This is important, as the build you are playing could depend on reaching specific ApS values making weapon choices important.

Calculating your ApS is simple. The two factors are multiplied together, and your ApS is calculated in the following way:

For the rest of this article, this ApS value is referred to when ApS is mentioned. Before we go into how Attack Speed affects your damage per second (henceforth DPS), we must elaborate on how the AS% functions and what happens when you add different sources. Do note that certain skills, such as channeled abilities, do not benefit from Attack Speed in any way.

Attack Speed% Cap

Attack Speed% is capped at 200% and further divided into two individual caps of 100%. For the sake of this article, we will call them “Cap 1” and “Cap 2”. That means that if you have 200% attack speed from Cap 1, you will only benefit from 100% of that attack speed. At the end of this section, you can see what Attack Speed sources belong to what cap. Make sure that you check what attack speed sources you have so you do not go over the cap!

Barbarian
Druid
Necromancer
Rogue
Sorcerer

Cap 1

  • Moonrise
  • Elixir of Advantage II
  • Attack Speed (Gear Affix)
  • Andariel's Visage
  • Wild Force
  • Brute
  • Duelist
  • Artillery Shrine (100% AS)

Cap 2

  • Accelerating
  • Rapid
  • Basic Attack Speed (Gear Affix)
  • Frenzy
  • Battle Frenzy
  • Battle Trance
  • Carnage
  • One-Handed Axe Expertise
  • Warrior's Rupture (Unverified)
  • One-Handed Sword Expertise (Unverified)
  • Walking Arsenal (Unverified)
  • Prime Call of the Ancients (Unverified)

Cap 1

  • Moonrise
  • Elixir of Advantage II
  • Attack Speed (Gear Affix)
  • Andariel's Visage
  • Nimble
  • Wild's Call
  • Ahavarion, Spear of Lycander
  • Swooping Attacks
  • Artillery Shrine (100% AS)

Cap 2

  • Accelerating
  • Rapid
  • Basic Attack Speed (Gear Affix)
  • Preserving Blood Howl
  • Enhanced Claw
  • Bestial Rampage
  • Enhanced Shred

Cap 1

  • Moonrise
  • Elixir of Advantage II
  • Attack Speed (Gear Affix)
  • Andariel's Visage
  • Kalan's Edict
  • Puppeteer
  • Frenzied Golem
  • Bone Golem Sacrifice
  • Culler
  • Artillery Shrine (100% AS)

Cap 2

  • Accelerating
  • Rapid
  • Rathma’s Chosen
  • Frenzied Dead
  • Enhanced Reap
  • Paranormal Blood Lance
  • Basic Attack Speed (Gear Affix)
  • Acolyte's Hemorrhage
  • Howl from Below: Corpse Attack Speed%

Cap 1

  • Moonrise
  • Close Quarters Combat (Cutthroat)
  • Flurry
  • Elixir of Advantage II
  • Attack Speed (Gear Affix)
  • Andariel's Visage
  • Culler
  • Nimble
  • Artillery Shrine (100% AS)

Cap 2

  • Close Quarters Combat (Marksman)
  • Alchemical Advantage
  • Accelerating
  • Asheara's Khanjar
  • Rapid
  • Haste
  • Basic Attack Speed (Gear Affix)
  • High Velocity

Cap 1

  • Moonrise
  • Elixir of Advantage II
  • Attack Speed (Gear Affix)
  • Andariel's Visage
  • Culler
  • Swift Conjurer
  • Ancient Flame
  • Ahavarion, Spear of Lycander
  • Artillery Shrine (100% AS)

Cap 2

  • Accelerating
  • Rapid
  • Prime Unstable Currents
  • Basic Attack Speed (Gear Affix)
  • Gloves of the Illuminator

Game Limitations & Skills per Second

Diablo 4's game engine is limited to checking the game state every 60 frames. In other words, every action in the game is calculated based on how many frames it takes for an action to happen, with the lowest being 1 frame and the highest having no cap. This means skills and abilities have different "frame times" at different ApS.

Using Rogue and Puncture as an example. The lowest ApS achievable for rogue is using two Swords with 1.1 Weapon ApS and no AS% from stats or paragon. Puncture at 1.1 ApS takes 26 frames to complete its full animation. You can convert this to Skills per Second (henceforth SpS) through the following formula:

SpS was theorized to be a hard cap of 5 skills per second. However, data collected shows that skills can go below that number. For example, Puncture has 10 frames at 2.9256 ApS which is achievable with daggers (1.2 weapon ApS) and 143.8% AS%. Using the formula above, 60/10 = 6 Punctures per Second, which disproves that 5 Skill casts per Second would be the hard cap for all spells.

Breakpoints

Finally, how does ApS affect your DPS? Due to the limitations of the game engine, the game cannot handle ApS values that put us between frames. This forces breakpoints, where, unless you meet the next breakpoint, further increasing ApS does not increase your DPS.

Let us use a practical example for this. Puncture has one breakpoint at 1.9056 ApS and another at 2.07 APS. If you use daggers, any attack speed between 58.8% AS and 72.49% will be useless as it does not bring you over 2.07 ApS.

So between 58.8% Attack Speed and 72.5% Attack Speed, you will not benefit from AS%. This means that when optimizing your damage, you want to be aware of these breakpoints to ensure that you do not opt into AS% that is not necessary. In this example, if you were to have 60% AS and add 15% AS, you would go from the 15-frame breakpoint to the 14-frame breakpoint. This would result in a DPS increase of 15 Frames / 14 Frames = 1.0714 = 7.14%. Instead, if you get enough attack speed to go from the 15-frame breakpoint to the 13-frame breakpoint, it would be a Damage per Second increase of 15/13 = 1.1538 = 15.38%.

The issue with these breakpoints is that they do not follow the expected formula. The expected formula would have been the following:

Here is a list of some of the approximations that are based on real data collected from the game:

  • Forceful Arrow, Heartseeker and Barrage roughly follow the formula: (Target Frames/32.26)^[1/(-0.962)]
  • Invigorating Strike roughly follows the formula: (Target Frames/36.172)^[1/(-0.966)]
  • Puncture roughly follows the formula: (Target Frames/28.146)^[1/(-0.957)]
  • Blade Shift roughly follows the formula: (Target Frames/20.12)^[1/(-0.92)]

These approximations were created by testing Attack Speed breakpoints by increasing AS% by 1.3% or lower, from 0% to roughly 165% AS. Even then, these approximations are not perfect and are between 1-2% AS% off. To ensure as accurate breakpoints as possible, every skill has to be manually extracted by adding small increments of AS%. The approximations above are close to the Expected Required APS formula but slightly off, making it clear that something is affecting the frame timings.

Breakpoint Tables

Here is a list of the currently known Attack Speed breakpoints for every single class that has been manually confirmed, as well as the approximations for the values that have not been extracted yet. The approximated values will have an (A) after them to show that they are not verified. Each class is divided into sections affected by APS breakpoints. This list is updated once new data is discovered, meaning it is considered an up-to-date reference to APS breakpoints.

Barbarian
Druid
Necromancer
Rogue
Sorcerer

To be added once data has been collected.

To be added once data has been collected.

To be added once data has been collected.

Basic Skills
Core Skills
Blade ShiftInvigorating StrikePunctureHeartseekerForceful Arrow
1.11.11.10.90.9
1.14181.12751.14180.92250.9225
1.21001.18251.16930.95670.9567
1.27561.21561.230.97920.9792
1.37401.261.39561.00171.0017
1.49161.30561.35961.03681.0368
1.59121.351.441.08001.0800
1.75081.41241.501.11421.1142
1.8961.45561.60561.15921.1592
2.12761.531.681.20421.2042
2.42761.591.801.261.26
2.69761.681.90561.30501.3050
3.19321.73402.071.351.35
3.7253 (A)1.84562.25961.41751.4175
1.96562.42761.48501.4850
2.05562.71201.55251.5525
2.20202.92561.64071.6407
2.32203.2917 (A)1.74151.7415
2.50203.7228 (A)1.84321.8432
2.65201.95751.9575
2.90762.04752.0475
3.10562.20502.2050
3.4290 (A)2.37422.3742
3.7846 (A)2.58502.5850
2.81932.8193
3.06 (A)3.06 (A)
3.3787 (A)3.3787 (A)
BarrageFlurryPenetrating ShotRapid FireTwisting Blades
0.9
0.9225
0.9567
0.9792
1.0017
1.0368
1.0800
1.1142
1.1592
1.2042
1.26
1.3050
1.35
1.4175
1.4850
1.5525
1.6407
1.7415
1.8432
1.9575
2.0475
2.2050
2.3742
2.5850
2.8193
3.06 (A)
3.3787 (A)

To be added once data has been collected.

Summary

  • Attack Speed% has two caps of 100%, which combined is 200%.
  • Attacks per Second is calculated by taking your Weapon Attacks per Second x (100% + Cap 1% AS + Cap 2% AS).
  • There are breakpoints for Attacks per Second, between which you have no gain from Attack Speed.
  • All breakpoints are not verified yet and will be included once they are extracted through testing.

Credits

Written by Avarilyn.
Reviewed by Dreadscythe, Northwar.

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