# Talk:Damage reduction

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## Armor Equivalency Edit

I have done some math after being in doubt about whether to choose a piece of gear with more armor or more stats. The result urged me to do some more math to discover whether there was a way to translate armor into a comparison with stamina directly. The resulting formula was

amount of hp equivalence gained by an increase of armor is equal to:

[i]HP/(1-((2*baseAGI+2*gearAGI+gearARMold)/(2*baseAGI+2*gearAGI+gearARMold+400+85*level))- HP/(1-((2*baseAGI+2*gearAGI+gearARMnew)/(2*baseAGI+2*gearAGI+gearARMnew+400+85*level))[/i]

This HP equivalence is equal to how much longer it would take a melee mob to kill you with your new increased armor. An attempt to engineer a level-dependant general formula became this:

[i]Level 1: 4850/HP=armor needed for 10 HP equivalence

Level 10: 12500/HP=armor needed for 10 HP equivalence

Level 19: 20150/HP=armor needed for 10 HP equivalence

Level 30: 29500/HP=armor needed for 10 HP equivalence

Level 41: 38850/HP=armor needed for 10 HP equivalence

Level 50: 46500/HP=armor needed for 10 HP equivalence

Level 59: 54150/HP=armor needed for 10 HP equivalence [/i]

I wish to add a paragraph dedicated to this principle but am unsure about whether it is 100% accurate, or could be simplified even more. Please look at it. --Tidal 16:58, 28 November 2007 (GMT)

I worked some more on my formula and finally came up with this extremely simplified, useful formula: Armor needed to gain extra survivability against physical damage equal to 10 HP =(4000+850*mobLEVEL)/(playerHP) This holds true for 1-59.

the chart at the very bottom of the page, in the "Armor required to get X% damage reduction" section, doesn't match the formulas. the armor cap against a 73 mob, for example, is 35880, not 35886, as the chart says. I'm going to go ahead and change this. --Tejing 16:26, 27 July 2007 (UTC)

## The most important thing .. Edit

... is apparently An X% increase in armor means an X% increase in the amount of damage you can take. But this seems to contradict the formulas on the page.

For example, say my level 32 paladin has 1947 armor. At level 32, the X value in the formula is 3120. The "damage I can take", I figure, is the ratio of damage dealt by the enemy, to damage taken by me. This is given by (X+A)/X. At my current stats, this is (3120+1947)/3120 = 1.624. Now, say my armor is increased by 10%, to 2142. That gives (X+A)/X = (3120+2142)/3120 = 1.6864. That's an increase over 1.624 of 3.85%, not 10%. Any help? Harveydrone ( talk | work ) 18:22, 31 July 2007 (UTC)

The statement on the page is definitely incorrect. Take the extreme example. Suppose you have 10000 hp and 1 armor. now increase your armor by 1. That's a 100% increase in armor, but it definitely not a 100% increase in the amount of damage you can take. (You go from being able to take 10000.8361 damage to being able to take 10001.6722 damage) What IS correct is that a X% increase in armor increases armor's contribution to your damage soak by X%. In the above example, 1 armor allows you to take 0.8361 more damage than you otherwise would be able to. Increasing that to 2 armor increases armor's contribution to your damage soak to double what it was (it's now 1.6722, precisely double 0.8361). I won't even go into the problems you'd run into with 0 armor using the stated "fact" :-P --Tejing 03:20, 4 August 2007 (UTC)

I think you are absolutely right, and that statement is wrong. I will illustrate it with two examples, using formulae/numbers taken from the page itself. (Before I go further note that there is an ambiguity with the symbol X as it's used in two different contexts on the page. It's used in the quote under discussion as a variable, as well as in the Damage Soak formulae as a symbol to lump together all the constant terms.)

Example 1: Damage Soak section formulae state that Damage_Dealt / Damage_Taken = 1 + ( Armor / X ), where X is a constant. That's fair enough. Example proceeds to state that an X increase in armor (compared to 0 armor) means a 100% increase in the amount of damage the player can take. In other words, you can take twice as much damage than a person without armor. Even that's correct. But now consider this: let's say you raise your armor to 2*X. This is a 100% increase in the amount of armor you have. However, by plugging into the above formula, the extra damage you can take rises from 100% to 200%, or in other words the total amount of damage you can take rises from two times (compared to without armor) to three times (compared to without armor). This is an increase by a factor of 1.5, in the total amount of damage you can take. In other words, in this extreme example, a 100% increase in armor causes a 50% increase in the total amount of damage you can take.

Example 2: Look at the damage reduction values at the bottom of the page, for Level 73 mobs. For 50% DR, you need 11960. If you have exactly 50% DR, then in order to double the amount of damage you can take (i.e. a 100% increase in damage taken), you would have to go up to 75% DR. This would require you to raise your armor to 35880, which is more than a 100% increase in your armor.

-- Lego 12:17, 2 August 2007 (UTC)

So maybe the "most important thing" ought to be more like this: when increasing armor, the amount of additional damage you can take is proportional to the amount of the armor increase. So say for example, with no armor you can take D damage. With X armor (the constant in the formula), you can take D more. With an additional X armor, you can take an additional D more, etc. Or, put another way: if I know that adding 100 armor will let me take 20 more damage, then adding another 100 armor will also let me take another 20 more damage. I'm not sure how to make that more succinct. -- Harveydrone ( talk | work ) 18:45, 3 August 2007 (UTC)

## Main graph is wrong Edit

The graph shown in the top right of the article is not correct for the formulas shown.

I'm going to upload a new updated graph. --Sleuth 13:15, 24 October 2007 (UTC)