DPS or Damage Per Second describes how much damage a character, spell, skill, ability or item can produce on average per second.
 Weapon Damage
All damage is calculated from weapon damage. This is significantly different from other games where spells and skills may have nothing to do with the damage of the weapon equipped.
Tooltip display for a weapon
The image to the right shows a typical weapon tooltip. The largest number is the weapon's DPS. Below that is listed the weapon's damage and attacks per second.
- NOTE: "Damage" and "Attacks Per Second" include all damage and Attack Speed % bonuses from magic affixes and gems.
To calculate DPS, you take the average damage from the range and multiply by the attacks per second.
- Example: 2-5 Damage = 3.5 average damage per attack. 3.5 * 1.40 attacks per second = 4.9 DPS
 Displayed DPS
On the character / inventory screen, the "Damage" displayed is your DPS after accounting for all of your skills, items, and other bonuses. Additionally, the tooltip on items allows you to instantly determine the change in this number in the +/- to damage section. As a result, the need to manually calculate DPS is usually not required, but can be helpful to understand the game better.
To calculate this number manually, determine your average damage per attack by totaling your minimum and maximum damages across all items (weapon, rings, off hand items, etc.) and dividing by 2.
- Base DPS (w/o Crit) = average damage per attack * attacks per second * attack speed % bonuses * primary attribute bonus * Damage bonuses from Skills
Over time, critical hits will raise your DPS.
- Total DPS = Base DPS * (1 + Critical Chance % * Critical Damage Bonus%)
 Dual Wielding
When a Barbarian, Monk, or Demon Hunter dual wields two weapons, each attack alternates between the two weapons. DPS can be calculated by calculating the DPS for each weapon and averaging the two, remembering to add the + 15 Attack Speed % bonus that is applied while dual wielding.
 Damage On Screen
When enabled, the damage delivered to a monster by each "hit" is displayed. This number shows the damage taken not the damage delivered, which is always at least partially mitigated by resistances and/or defense.
 DPS Calculation Complications
The DPS displayed on the character / inventory screen is further modified by the character's active skills. While the tooltips for these skills provide explanations of overt changes to damage (X% of weapon damage), the mechanics of each skill vary. Some skills are able to target multiple enemies and some deal damage over time.
 DPS Class Role
In other games, a class role refers to a class or character build that achieves a specific goal during group combat. There are generally four types of these classes: a tank, a healer, crowd control, and DPS. The role of the DPS player is to inflict as much damage as possible to the enemy or enemies in the area. The tank keeps the enemy's attention, keeping the enemies from damaging other party members, and the healer keeps everyone alive during the entire process.
All classes in the Diablo games are designed as DPS classes, capable of dealing out big damage and clearing any difficulty playing solo.