Armor and Magic Resist Questions

Düff McWhalen·Sep 4, 2019·1 votes·1,765 views

Is the damage reduction % based, or do I mitigate 1 AD per 1 Armor? I'd like to be able to better calculate what amount of resistance actually has an effect on me living longer in games.

8 Comments

BlackKnightJackSep 4, 20191 votes

It's percent based. You can tell by hovering over the stat in game.

Cind3rkickSep 4, 20191 votes

It's percentage based with a diminishing effect. So 40 to 50 armour is a bigger difference than 100 to 110

Darkdemon653Sep 4, 20195 votes

{quoted}

It's percentage based with a diminishing effect. So 40 to 50 armour is a bigger difference than 100 to 110

I have to jump in and correct this/make sure you meant something else.

Resistances do not have diminishing returns. Ignoring penetration/reduction, 1 point of armor will ALWAYS increase one's effective health against physical damage by 1% of one's total health. While the numerical value of the percent reduction goes up more slowly as resistances increase, the significance of changes in numerical value also go up. Going from 0% reduction (0 armor) to 50% reduction (100 armor) provides the exact same benefit as going from 50% reduction (100 armor) to 66.67% reduction (200 armor).

If that's what you meant, that's fine. I've spent many years trying to quelch the incorrect idea of resistances (and things that use the same or a similar formula) having diminishing returns (in multiple games), so I have to pounce when I see the idea potentially being thought and spread.

pro crastinat0rSep 4, 20191 votes

Beat me to it haha

WoonStruckSep 5, 20191 votes

People don't seem to understand that if armor/mr have "diminishing returns" as they see it (they don't), you have to apply the same logic to AD, AP, and HP.

10 AD at 100 total AD is only a 10% increase, while 10 AD at 200 total AD is only a 5% increase.

People like to think in terms of relativity for armor/mr, but not the other stats for some reason. [sg-lux-2]

pro crastinat0rSep 4, 20191 votes

On an effective health basis, armor does not give diminishing returns. +1 armor gives + 1% effective health.

Ignoring armor reduction stats because they just complicate the calculation.

Say you start with 0 armor and 1000hp

It will take 1000 base damage to kill you

Add 50 armor and plug this into the resistance formula and you get receive 67% of the base damage, meaning it will take 1500 base damage to kill you, a 500 increase in effective hps.

Add another 50 and you will receive 50% of the base damage, meaning it will take 2000 base damage to kill you. So the additional armor still added 500 effective hps even though you went from 50-100 instead if 0-50

pro crastinat0rSep 4, 20191 votes

Damage = base damage * 100/(100 + resistance)

Or if resistance is negative

Damage = base damage * (2 - 100/(100 - resistance))

Resistance = (base resistance - flat shred) * (100% - %shred)/100% * (100% - %pen)/100% - flat pen

WoonStruckSep 5, 20191 votes

The easiest way to think about it is as health.

1 armor/mr= 1 hp for every 100 HP you have.

The % reduction value it gives is a representative value.

#You do not gain less out of each additional point of armor/mr.

You gain exactly 1% of your HP as additional effective health vs the respective damage type.

However, there are thresholds where straight health will be more effective than armor/MR as far as gold translating to EHP efficiently.