We have properties, trait(Barkskin), talents, passive abilities, and ult (IronBreaker), that give you damage reduction. Does anyone know how to calculate damage reduction? Which of those stack, and which is not?

If I remember correctly, the barkskin trait is caculated after your passive and necklace properties.

There seems to be lots of random information about this but from what i read way back it pretty much goes from talents to items to traits and then there is some bizarre ones like ironbreakers ult passive which seems to go somewhere.

None of them should simply stack so you cant go 100 % immune to damage.

This was a calculation that was brought up for a conversation about the changes to Barkskin when it first came up. Iâ€™m not 100% sure that itâ€™s accurate, but itâ€™s certainly a starting point. Iâ€™ve been basing my DR calculations on it for months, so Iâ€™d love to be told Iâ€™m doing it correctly and Iâ€™d also love to be corrected so I can do it right

More or less, I think it comes across as the largest source of DR to the smallest, but Iâ€™m no expert in the area.

Also, is it possible to have damage reduction against chaos and skaven on necklace in the same time?

P.S. Found answer: noâ€¦

Specifically for properties, they arenâ€™t two properties simply picked out of the same pool: they are a each a single property that is drawn from their own pool. Sometimes those pools overlap, but there are certain things that only exist in one pool, one of which is "Damage reduction versus "

Both "DR vs. " exist in the same pool of property 1 but not in the pool of property 2, so it is not possible to draw many combinations because the second property, desired or no, doesnâ€™t exist in the other properties pool of choices.

So, thatâ€™s the long winded answer of no, but you already knew that so I tried to extrapolate and explain why

No, I did not know about this pools specifically, so thank you for enlightenment.

Only goes to show that, like with â€śdamage vs. skaven and chaosâ€ť, someone hugeley overestimated how mighty and useful this combination would be. Even if it was possible to get, it is safe to assume that MAYBE people would run it on Ironbreaker together with (the then completely different) barkskin - and since DR isnâ€™t additive, but multiplicative (at least sort of), 10% more DR against anything is still hardly worth it when compared to 20% more health. I run health and DR vs. area damage on IB mainly for the lulz (I found that I needed neither more stamina nor BCR or block angle, since an offensive IB is an absolute battering ram and nearly impossible to kill), but being next to invulnerable to warpfire, gas and stormfiend flames and troll bile is something that comes in very handy if you run with 2h hammer or axe and drakecannon, so youâ€™re always very well in range of these threats when engaging these enemies.

The DR on necklace could use some rework. I think it should either be DR vs. armour class or simply just one â€śdamage reduction vs. direct damageâ€ť and â€śdamage reduction vs. area damageâ€ť, with area damage being 10 to 20% and damage reduction vs. direct damage staying at 5 to 10.

While we are at it, does FK with his two passive damage reductions also work this way? It would explain why he sometimes feels squishier in the DR department even when stacked to â€ś30%â€ť damage reduction from passive and aura.

You are pretty much spot on that 20% HP usually takes the cake, but DR (despite itâ€™s diminishing returns if you already have a lot of sources of it) is effectively more HP. I agree with you, but with the right variables 10% DR can become an effective 50-60HP.

Iâ€™m ripping this right out of @KaizenDKâ€™s post, but itâ€™s a cool informational piece and I never thought about it this way until he explained it to me.

In summary of the image: if you have 50% DR, you effectively have twice as much HP. Each 1% DR, despite not actually changing anything (it just takes 1 more point of damage off of a 100 damage attack), translates to being more and more effective when stacked. Funny enough it also effects all healing received.

That 10% DR, if you are already mitigating 50% of damage taken, only reduces the damage taken by 5% (according to what Iâ€™ve been doing and my math could be wrong) but gives you an effective 25% additional HP.

SORRY FOR THE LONG TANGENT but I think itâ€™s another multiplicative thing for Foot Knight and his Aura. If the attack does 100 damage:

Passive Damage Reduction:

(100*.15) = 15 damage reduction, leaving 85 still coming through

Aura Damage Reduction:

(85*.15) = 12.75 damage reduction, 72.25 still coming through

Again, I might be terribly wrong so please correct me if you know!

Foot Knight have exactly 30% DR (with additional 5% from talent).

From overhead strike you will receive 70 damage of 100. Tested.