Minecraft wiki entry for Armor, associated text: One piece of diamond armor (granting +2 toughness) decreases the defense reduction value for each attack hit point to 1.6%. Two diamond pieces decrease it to 4⁄3% (about 1.3333%), three decrease it to 8⁄7% (about 1.1428%), and four decrease it to 1%. Netherite armor decreases this even further. One piece of netherite armor reduce the defense reduction value for every hit point to 16⁄11 (about 1.4545%), two decrease it to 8⁄7 (about 1.1428%), three decrease to 16⁄17 (about 0.9412%) and four decrease it to 0.8%. The exact formula for the defense reduction in percent is: