Diablo 3′s damage system is really easy to do your own calculations for, while there are also several advanced spreadsheet based DPS calculators you can actually do it all by hand or even make your own spreadsheet. It’s always better to understand how DPS is calculated opposed to just depending on a spreadsheet. Here is how DPS is calculated in Diablo 3.
There are five major figures involved in calculating your damage output: Average Damage, Attacks per Second, Stats, Skill Modifiers and Critical Strikes
Your average damage is all the damage on your weapon, off-hand, weapon’s gem, rings and amulets. Currently those are the only those equipment types (with some exceptions, like legendary equipment) that can have the +X-Y damage style modifier on them. You can calculate your weapon damage by adding up all the of minimum and maximum damage stats across all of your gear.
Your average damage is your total minimum damage plus your total maximum damage divided by 2. Like this:
Once you know your average damage you can calculate your actual base DPS by multiplying by your attacks per second. Your base DPS is probably the most important stat you can increase, since all the modifiers listed below are applied to your base DPS.
Attacks per Second
In the step above, it does not matter what type of weapon you are using. Whether it’s 1handed or 2handed. The only aspect of your weapon type that matter is the Attacks per Second. Your weapon’s tooltip will list it’s attacks per second (keep in mind this includes +attack speed modifiers on that weapon). If you have a 1.40 attacks per second on your weapon, then that’s your base attacks per second.
Next, add up all your + Attack Speed modifiers. On my Demon Hunter he has a base attack speed for 1.40, gloves with +7% and a Quiver with +15%. I add 7% to 15% and get 22%. Then I apply this like this:
modifier attack speed = base attacks per second * (1 + total attack speed modifiers)
1.708 = 1.40 * (1 + .07 + .15)
In this case it’s 1.708 or rounded to 1.71. You can check your math by looking in your character’s details. The attacks per second there reflects all your modifiers.
You can now calculate your base DPS by multiplying your average damage by your attacks per second. In this case it’s 771 * 1.708 or 1316.868 DPS. After that we get to apply skills, stats and crit.
You probably know by now that Monks and Demon Hunters use Dexterity, Barbarians use Strength and Witch Doctors and Wizards use Intelligence. Each point of these stats adds 1% of your base DPS.
If you have 100 of your primary stat you get to increase your dps by 100% or multiply it by a factor of 2. Here is the math you would use to calculate the stats modifier:
stat modifier = 1 + (stat/100)
If you had 123 Intelligence as a Wizard, you would have a stat modifier of 1 + 1.23 or 2.23.
Your skills also contribute to your overall damage per second. You’ll see it right in the tooltip. For example Archery increases my Demon Hunter’s damage by 15% if I use a bow. That makes my skill modifier 15% or 1.15 (1+15%). You can figure out your skills modifier by going into the details of your character.
Finally your critical strikes are very important. If you have a critical hit chance of 50% and critical damage of +90% your critical damage modifier will increase your DPS by 45%. This is because 50% of the time you will do 90% more damage.
Your crit modifier can be calculated like this:
crit modifier = 1 + (crit chance * crit damage)
1.45 = 1 + (0.5 * 0.9)
Adding it All Up
Now you can take your base DPS and multiply it by your stats modifier, skills modifier and crit modifier. Using the examples above:
overall DPS = base DPS * stat modifier * skill modifier * crit modifier
2700.93 = 1316.87 * 1.23 * 1.15 * 1.45
As you can see your most important stat is your base damage which is a direct result of your average damage (from damage modifiers) and your attacks per second (from your weapon and your attack speed modifiers). This is why attack speed is so powerful and sought after.
Important: Many of the strategies and tips I share here were originally inspired by the people at the Diablo 3 Gold Secrets Forum. If you're serious about making the big bucks in Diablo 3, or just being the best players, you need to signup ASAP.