The armor cap

I've been researching the armor damage reduction mechanics and wanted to share the verified formula that I've tested extensively in-game.

This formula has been verified through extensive testing and matches the observed damage reduction in actual gameplay scenarios.

To calculate the actual damage taken from an attack:

Key points about this formula:

• The armor cap for damage reduction is 75% maximum
• Higher level attackers require significantly more armor for the same reduction percentage
• The formula applies to all physical damage sources
• Magic damage completely bypasses armor

This has been tested against level 63 mobs (typical raid boss level) and the calculations match observed damage reduction perfectly.

This is incredibly useful! I've been wondering why my damage reduction seemed inconsistent against different level mobs. The level-based scaling in the denominator explains everything.

So for a level 60 attacker, you'd need:

But against level 63 raid bosses, you need 17,265 armor as shown in your example. That's a significant difference!

Excellent work on the formula verification! This matches the data I've been collecting as well.

For those interested in the practical implications:

• Every point of armor provides the same effective health increase
• While the percentage reduction has diminishing returns, survivability increases linearly
• This makes armor incredibly valuable for tanks, even at high values

The formula r = a / (a + 400 + 85 × b) is fundamental to understanding tank gearing in Classic WoW.