Health Percent Damage

Health Percent Damage

Health Percent Damage (HP%DMG) is an ability found on some items and weapons that makes hits deal additional damage based on the target's current HP.

Usually the effect deals 10% of an enemy's current health as bonus damage, and 1% of the enemy's current health as damage if the target is an Elite or Boss. But it also exists with higher amounts.

Health Percent Damage is applied after all other damage modifier and cannot be increased by any stat. In Endless Mode the effectiveness of HP%DMG declaines to the point where it stops dealing significant damage. See the table below.

Sources of HP %DMG

There's two options for dealing HP%DMG with items.

Name	Rarity	Effects	Base Price	Limit	Unlocked By	Tags
Giant Belt	Tier 4	Critical hits deal 10% of an enemy’s current health as bonus damage (1% for bosses and elites)	110	1	Win a run with Jack	Crit Chance
Greek Fire	Tier 4	Burning deals an additional 10% of current enemy HP as damage (1% for bosses and elites)	100	1		Elemental Damage

Chainsaw is currently the only Weapon that deals HP%DMG. It deals 10%/1% at Tier 3 and 20%/2% at Tier 4.

Name	Class	Damage	Attack Speed	DPS	Crit Damage/Chance	Range	Knockback	Lifesteal	Special Effects	Base price	Unlocked by
Chainsaw(DLC)	Blade, Tool	- - 10(+75%+75%+75%) 20(+100%+100%+100%)	- - 0.53s 0.56s	-- -- 18.8(141.3%141.3%141.3%)/s 35.9(179.3%179.3%179.3%)/s	- - x1.5 (3% chance) x1.5 (3% chance)	- - 175 200	- - 0 0	- - 15% 30%	Deals 10%/20% of an enemy’s current health as bonus damage (1%/2% for bosses and elites)	- - 112 242	Default

Strategy and Mechanics

Generally speaking HP%DMG is quite powerful. The extra damage to regular enemies is decent. The damage to Bosses and Elites is much more important. Even at the 1 to 10 ratio, the biggest impact of HP%DMG is that it allows builds to kill Elites and Bosses with much more ease. Adding a Chainsaw to a build that otherwise couldn't kill an Elite often makes a huge difference and makes it much more doable.

Giant Belt and Greek Fire are generally speaking some of the most powerful things you can find if you're on a Crit build for the Giant Belt, or Burn build for Greek Fire.

Works with Structures

You can make Structures crit using Pile of Books. If you have Giant Belt, then your structures' crits will deal the bonus damage of the giant belt.

You can also trigger Greek Fire with structures. Incendiary Turret's blue fire triggers it. And if you have Scared Sausage, your structures can inflict burn on hit, which triggers greek fire.

Cannot be modified

You cannot increase the damage done by HP%DMG. It isn't modified by anything.

The Damage dealt by HP%DMG isn't increased by % Damage, or multiplied by Critical Hits. It isn't increased by Silver Bullet, or Small Fish.

Cursed

When Cursed, the HP%DMG damage effect is multiplied by the Curse boost. So 10%/1% (Regular/Elite) damage per hit can be increased all the way to 21%/2.1%. Note that the 10 to 1 ratio between damage to regular enemies and damage to elite/bosses is kept.

Endless Scaling

All sources of Health Percent Damage are coded to lose effectiveness when you get to the higher levels of Endless Mode. Starting at wave 39, the effect begins to deal less than what's stated on the tooltip. You can see the percentage of effectiveness below:

Wave	1-38	39	40	45	50	60	75	100
Effectiveness	100%	94%	79%	38%	22%	9%	3%	1%