Healing Amplification

Healing Amplification increases the hit points cured by healing spells and effects. It stacks with effects that increase the power of healing spells, such as metamagic feats (e.g. Empower Healing), class enhancements (e.g. Cleric Life Magic), item enchantments (e.g. Devotion), scroll mastery enhancement, etc. Incoming healing is simply multiplied by character's total healing amplification.

Healing amplification comes from race, class, items, and miscellaneous sources. These stack, but special rules apply.

Total heal amp = racial amp * class amp * item amp * misc (* misc) (* misc) ...

Racial bonus
Most races don't have racial bonuses to healing amplification, i.e. their racial multiplier is 1.
 * Human Improved Recovery has 3 tiers (10/20/30 %) for a maximum multiplier of 1.3.
 * Half-elves can take 2 tiers of Human Improved Recovery for a maximum multiplier of 1.2.
 * Warforged start at 0.5 and can take Healer's Friend enhancements (three tiers 15/20/25 %) for a maximum racial multiplier of 0.75.
 * Docent of Blood is an item, but stacks differently than most items. Its 0.1 (10%) is added to Warforged racial heal amp, for a total of 0.85 (when Healer's Friend is maxed)

Class bonus
Class bonuses from different classes stack (are multiplied).
 * Monk Improved Recovery has 3 tiers (10/20/30 %) for a maximum multiplier of 1.3.
 * Half-Elf Monk Dilettante enhancements (Half-Elf Improved Recovery) has 2 tiers (10/20 %), max. 1.2. (This is a class bonus, stacks with racial, locks out monk's amplification)
 * Paladin prestige enhancement Hunter of the Dead (10% per tier of the PrE)

Item bonus
The healing amplification item enhancement comes in three levels (10/20/30 %). Items with the same level do not stack. Items with various levels of healing amplification stack. The bonuses are multiplied, for a total of 1.1 * 1.2 * 1.3 = 1.716.

Healing amplification 10%
 * Dragontouched Armor, Eldritch
 * Greensteel Weapon - Tier 1
 * Vengeful Protector

Healing amplification 20%
 * Tira's Splendor rune arm
 * Dragontouched Armor, Tempest
 * Greensteel Weapon - Tier 2
 * Levik's Bracers (From Hound of Xoriat raid)
 * Can be crafted on Tower of Despair Rings (Incredible Potential)
 * Epic Bejeweled Letter Opener

Healing amplification 30%
 * Greensteel Weapon - Tier 3
 * Epic Gloves of the Claw

Miscellaneous bonus

 * Paladin Passive Past Life Feat (stacks 3 times, for a total of 1.05^3 = 1.157625)
 * Jidz-Tet'ka - +25% insight bonus for Monks in fire stance.
 * House Jorasco Healer Contract from Guild Airships (10 %)
 * Fleshmaker (10%) item enchantment found on the Finger Necklace, Fleshshaper's Brigandine or Fleshshaper's Docent has a unique mechanics and stacks. For best effect, equip the fleshmaker item first and then add other sources of healing amplification. When done this way, it will provide quite a bit more then 10% in total, as it works as a multiplier applying before all your other healing amplification gear.