Dealing damage in Diablo 4 is roughly half the game. Some would even say it's more than that, after all, the demons won't kill themselves. You need to do it by bringing their Life to 0 and there's no better way to do it than damage! In this article we describe how damage is calculated and the many different ways to deal more damage.

We need to start our damage calculation somewhere and depending on the source of damage there are two ways to do that.

Skills and passives scale their damage based on your weapon. In the advanced skill tooltip (a setting you need to check in the menu), you can see a percentage next to the damage number. Multiply that percentage by the damage value on your weapon and you get the damage that you deal with that skill. If you use multiple weapons, the damage of both weapons is added together.

Here, skill% is the number you see in your skill description with advanced tooltips enabled. It depends on the skill used and the number of ranks you have invested into it. DMG_weapon is dependent on weapon type and its item power. Note that weapons have a damage range instead of a single damage number; for these calculations you can take anything: minimum, maximum, or average damage. The math stays the same.

Some effects, such as Thorns or procs from certain Legendary Aspects (e.g. Arrow Storms or Trickster's), deal damage that doesn't depend on your weapon. Instead, they just have a flat value that is used as a base for the damage calculation, same goes for your Thorns.

or

Similar to DMG_weapon, both Thorns and Legendary Aspect procs scale with item power.

Next, we have a number of various damage bonuses coming from our items, Glyphs, and paragon nodes. One thing all of these have in common is that there's no "x" before the percentage. This means that all these damage bonuses are additive.

The following damage bonuses belong to this additive category:

The important takeaway here is that all these bonuses don't provide as much benefit as you would think at a glance. An item saying +20% Core Skill Damage will give you less than 20% damage increase even if you deal all your damage with a Core skill, and the more you stack these bonuses, the less effective they become. This becomes especially noticeable in the late game when you get tons of additive damage bonuses from your Paragon Boards and Glyphs.

Many bonuses, however, have a slightly different wording. They say: "x30% increased damage if this and that condition is met". This means that the bonus in question is multiplicative. You get exactly what it says on the tin. x30% means 30% bigger number on your screen when the condition is fulfilled.

There's exactly one bonus that acts as a separate multiplier without having an "x" before its value. It is the Skill Damage bonus you get from your main Core Stat.

After adding multiplicative bonuses our damage formula becomes:

Important: some Passives and Legendary Aspects that provide multiplicative bonuses also show up in your character stats. For example the Offensive Aspect of Inner Calm will increase your All Damage stat by 30% multiplicatively. This is incorrect and misleading! Your All Damage gained from items and paragons is still additive and your Aspect provides a 30% increase to your total damage, including all additive bonuses and not just All Damage.

Some skills can make enemies Vulnerable (their Life bar turns purple, or if you are affected, your Health Orb gets cracks). In this state, enemies take 20% more damage from all sources. This 20% is a separate multiplier, the rest of "Vulnerable Damage" bonuses are additive damage that only becomes active against Vulnerable targets, similar to how "Damage vs Burning Enemies" only works when enemies are on fire.

All damage can be divided into direct damage and Damage over Time (Burning, Bleeding, Poisoning). Direct damage happens instantly, while damage over time is spread over a set duration. We didn't mention this distinction earlier because in terms of numbers and buffs, direct damage and DoTs behave exactly the same, up until we get to the topic of Critical Strikes. Only direct damage can Critically Strike, Damage over Time cannot.

Each hit has a random chance to be a Critical Strike. This chance is equal to your Critical Strike Chance (CSC) stat, which can be increased in many different ways: You get 5% baseline, 0.02% for each point of Dexterity or Intelligence depending on class, rolls on Gloves and Rings, and many skills and passives.

When you trigger a Critical Strike your damage is multiplied by x1.5 and all your Critical Strike Damage bonuses are added to the pile.

In other words, Critical Strikes simply add one more multiplier to the list of your multiplicative [x] bonuses and a bunch more (depending on how much Crit Damage you stack) to your total sum of additive damage.

Critical Strike Damage is no different from any other type of additive damage and you can very easily compare them. Whatever has biggest value multiplied by uptime is better. (as a bonus, for CSC you always know the exact uptime - your Crit Chance). To evaluate the effectiveness of Crit Chance you have to look at your Crit Chance, Crit Damage, Total Additive Damage, and separate Multipliers that have crit as a condition (e.g. Heavy Handed or Aspect of Three Curses). As a rule of thumb, a single 7.5% roll of Crit Chance translates to 3.5% damage increase, which is slightly better than competing 20-30% additive damage rolls. With more Crit Damage and Crit Multiplies, Crit Chance pulls even further ahead.

On top of Critical Strikes, there's another mechanic that lets you randomly get a 1.5x separate multiplier. There are several key differences between Overpower and Critical Strike. First of all, Chance to Overpower is not a stat, it's just a fixed 3% chance with no way to increase it. Instead, some skills have guaranteed Overpower when conditions are met. Second, besides the explicit "Overpower Damage" bonuses, your Overpowered attack benefit from extra additive damage that is based on your Current Life and Fortify:

For example, a fully Fortified character, whose Max Life is equal to 200% of their Base Life will receive +600% damage bonus to their Overpowered attacks (200% from Life rule and 400% from Fortify rule).

Not related to the damage calculation, but there's one more difference between Overpower and Crits. Crits happen per target hit while Overpower happens per attack. This means that one attack hitting multiple enemies or multiple times will always Overpower (if you proc that 3% chance when you use it). As an unfortunate side effect of this system, Channeled Skills and DoTs are unable to Overpower.

One more stat that doesn't directly contribute to your damage, but does affect your Damage Per Second (DPS) is Weapon Speed. Your Weapon Speed indicates how often you can cast your skills (although some skills have fixed animation length not dependent on Weapon Speed). To calculate your Weapon Speed you need to consider two parameters: your weapon's Attacks per Second (APS), which is averaged when dual-wielding, and your Attack Speed bonus. Attack Speed can roll as a stat on your Gloves and also comes from different skills, passives, Paragon nodes, and Legendary Aspects. For Basic Skills specifically, there's also a special stat called Basic Skill Attack Speed. Your Attack Speed Bonus is capped at 100%. Basic Skill Attack Speed and Accelerating Offensive Aspect can go over this cap. All these bonuses are added together and act as a multiplier to your weapon's Attacks per Second:

Now for direct damage skills you get a very simple DPS formula:

More or less the same applies to DoT skills that can stack, except the actual damage is delayed by the DoT's duration. For non-stacking DoTs, Weapon Speed doesn't affect damage at all.

The game offers you an approximation of your DPS called Attack Power, which you can see in your inventory window. However, you shouldn't rely on this number except as a very rough guideline. It doesn't include a lot of damage bonuses, specifically those that apply only to certain skills or against certain enemies. It also doesn't include any debuffs you can have on monsters such as Vulnerable. On the other hand, it includes your Weapon Speed and Critical Strike stats, which can be very misleading if your damage comes from a DoT or a skill with fixed animation length.

To get the Big Number^tm you need to get yourself a good weapon, a powerful skill, and stack a lot of different damage bonuses, preferably those that have "x" in front of the percentage. Then you need to hit something over and over until you proc both Critical Strike and Overpower with the same attack. At that point you only need to take a screenshot and post it online. Everyone will be impressed.

Written by Northwar.
Reviewed by wudijo, snail.