Quote Originally Posted by MaAaT View Post
I believe it's even 18.5k armor, not sure tho. Idk if the dmg reduction is linear or exponential. That would change everything.
I just found a post about this and it seems to be linear.
"Armor cap is around 17,500 for 86. Cap armor used (last checked at 81 cap) to decrease taken damage by 80%. This means 1,000 damage at 0 armor is being reduced to 200 damage at 17,500 armor in level 86 maps.

Damage regression is linear meaning everything below 17,500 armor can be converted straight into the reduction multiplier by rules of proportion. For example 8,750 armor reduces damage by 40% or 13,125 armor reduces damage by 60% at 86.

I believe it works like this but haven't tested at 86 cap yet."
Credit to QuaseT
This means that more armor is always worth it.