So I have been thinking for awhile of a formula to figure out how much unmitigated damage you can take per second through mitigation and life regen. Mostly how much dmg from Rend or Haunt can you take per second without losing life.

Simple

(Life Regen per sec/(1 - Total Damage Reduction %))

Advanced

Life Regen per Sec/ (1- (Total Armor/ 3150 + Total Armor)) * (1 - (Total Resist/ 315 + Total Resist)) * (either .65 for Barbs/Monks or .70 for WD/DH/Wiz) * (1 - Elite dmg reduction %) * (1 - Ranged dmg reduction %) * (1 - Any additional reductions such as Jungle Fortitude)

Not sure any dot dmg is considered melee.

The way Elite dmg and ranged reduction is calculated is on a piece by piece calculation. So if you have one piece of elite reduction that is 7% it is 1 - .07 so it is .93. But let's say you have BT boot's with 7%, 7% from litany, 7% from BT set, and 7% from storm shield. It is calculated as

(1 - .07) * (1 - .07) * (1 - .07) * (1 - .07) or .93^4 being 0.74805201

Now D3up is a good place to get your damage reduction numbers for Armor and Res. Just remember though for Monk's and Barbs the 30% is already calculated in so you will have to * your dmg reduction by .95 and for WD/DH/Wiz by .7

The damage reduction percents though when you look at your characters in D3 are wrong. They are based on level 60 monsters when they should be calculated on level 63 monsters.

A couple of examples

First my WD BigBadVooDoo

(2,620 Life per sec)/ ( (1 - (3,751 / 6901)) * (1 - (782 / 1097)) * 0.7 * .93 * (1-.15)(JF) )

2620/ ((.4565) * (.2872) * .7 * .93 * 85 )

2520/.0725

34,759 dmg per sec I can absorb simply by my regen.

Second example

Someone with a ton of regen and mitigation

Arndawg's Barb

http://us.battle.net/d3/en/profile/arndawg-1193/hero/17180467

Now it is best to assume he will have WarCry up always and to include Inspiring Presence in his calculations of Life Regen per second.

5,180 / ( ( 1 - (11,072/14,222)) * (1 - (1000/1315)) * .65 * (.93 * .93 * .94 * .93) * (.94) )

5,180 / .2215 * .2395 * .65 * .7561 * .94

5,180 / .0245

211,429 dmg per second

Now let's calculate to see what it is with Ignore Pain up

5,180 / (.0245 * (1 - .65)

5,180 / .008575

604,082 dmg per second

Hopefully someone more talented with spreadsheets could somehow implement this. Let me know if I made any mistakes.

Simple

(Life Regen per sec/(1 - Total Damage Reduction %))

Advanced

Life Regen per Sec/ (1- (Total Armor/ 3150 + Total Armor)) * (1 - (Total Resist/ 315 + Total Resist)) * (either .65 for Barbs/Monks or .70 for WD/DH/Wiz) * (1 - Elite dmg reduction %) * (1 - Ranged dmg reduction %) * (1 - Any additional reductions such as Jungle Fortitude)

Not sure any dot dmg is considered melee.

The way Elite dmg and ranged reduction is calculated is on a piece by piece calculation. So if you have one piece of elite reduction that is 7% it is 1 - .07 so it is .93. But let's say you have BT boot's with 7%, 7% from litany, 7% from BT set, and 7% from storm shield. It is calculated as

(1 - .07) * (1 - .07) * (1 - .07) * (1 - .07) or .93^4 being 0.74805201

Now D3up is a good place to get your damage reduction numbers for Armor and Res. Just remember though for Monk's and Barbs the 30% is already calculated in so you will have to * your dmg reduction by .95 and for WD/DH/Wiz by .7

The damage reduction percents though when you look at your characters in D3 are wrong. They are based on level 60 monsters when they should be calculated on level 63 monsters.

A couple of examples

First my WD BigBadVooDoo

(2,620 Life per sec)/ ( (1 - (3,751 / 6901)) * (1 - (782 / 1097)) * 0.7 * .93 * (1-.15)(JF) )

2620/ ((.4565) * (.2872) * .7 * .93 * 85 )

2520/.0725

34,759 dmg per sec I can absorb simply by my regen.

Second example

Someone with a ton of regen and mitigation

Arndawg's Barb

http://us.battle.net/d3/en/profile/arndawg-1193/hero/17180467

Now it is best to assume he will have WarCry up always and to include Inspiring Presence in his calculations of Life Regen per second.

5,180 / ( ( 1 - (11,072/14,222)) * (1 - (1000/1315)) * .65 * (.93 * .93 * .94 * .93) * (.94) )

5,180 / .2215 * .2395 * .65 * .7561 * .94

5,180 / .0245

211,429 dmg per second

Now let's calculate to see what it is with Ignore Pain up

5,180 / (.0245 * (1 - .65)

5,180 / .008575

604,082 dmg per second

Hopefully someone more talented with spreadsheets could somehow implement this. Let me know if I made any mistakes.