Math help; damage reduction

[(PSN)theelix]

I'm trying to find out how to calculate an effective increase.

For example, which is also what I'm trying to figure out, I have an Excalibur at base (225) armor. I want to see if I'd get more damage reduction by increasing his armor with a max Steel Fiber(472) or by using a flat 12% damage reduction mod.

If you wouldn't mind leaving a formula, that would be appreciated.

In case anyone needs a reminder, Armor is calculated: Net Armor / (300 + Net Armor), so it would be 225 / (300 + 225) essentially, not factoring resistances and bonuses of damage types and etc.

[(PSN)Cwellann]

Don't try to do damage reduction.  The curve's exponential decay.  Pain in the butt.  Use Effective Health Instead.  Linear.  Nice.  Easy.  Fun.

Let nominal Health be H, let Effective Health be E, let armor be A.
Then, E=H(1+(A/300))
You'll note that increasing armor by 300 points will give you an additional base health pool each time

I'm assuming you're using Vitality, because of course you are.
H=740, A=472
E=740(1+(472/300))=1904
Also note, Quick Thinking is affected by your armor, just in case you're planning on going that route.

12% damage reduction? (by the way, my brain's fried, so I have no idea what mod this is)
740/(1-0.12)=841
Additionally, something to keep in mind is you get 60% damage reduction on all front facing incoming damage while EB is active.  With Quick Thinking, Primed Flow, SF, and Vitality, and EB out, comes out to:
E=[(740+(425*2.4))(1+(472/300))]/(1-0.6)=11322 effective health (provided all damage taken is to the face, and I'm not sure how Warframe rounds).  Not bad.  Not Chroma, but not bad, works pretty decently with Rage.

Spoiler

Unless I got something wrong.  Long day.  That looks pretty much it though.

 

Edited April 21, 2016 by (PS4)Cwellann
spelling

[(PSN)theelix]

Though I never found the formula, I found that it's an effective 7% increase if I use the mod, while using Steel Fiber I get a total 18% increase.

Yay math.