Damage

Damage refers to the amount of damage each tear deals to enemies, and is represented by a sword. As damage increases, the size of the tears increases as well. However, tear size is not always a valid indication of how much damage your tears will do, a good example of this is Tropicamide. Tears will grow and shrink when your damage changes, but tears of a certain size do not have a specific damage value, and two tears of the same size (in two different runs) are likely to have different damage values.

Polyphemus is an example of an item that provides a very high Damage stat.

Effective Damage[]

The formula for damage is: $\color {white}{\mathit {EffectiveDamage}}={\mathit {CharBaseDmg}}\times {\sqrt {{\mathit {TotalDmgUps}}\times 1.2+1}}+{\mathit {FlatDmgUps}}$

where:

CharBaseDmg = The character's base damage multiplied by their multiplier,
TotalDmgUps = the total of all regular damage ups collected (not including special exceptions or damage multipliers),
FlatDmgUps = the total of all damage ups that are excluded from the above (for example, Curved Horn or Ipecac), and
EffectiveDmg = the approximate damage that can be expected per tear, or per 'tick' when using Brimstone or Technology 2.

This formula makes most damage upgrades less potent the more that Isaac has. For example, a Pentagram on Isaac would make his total damage (1 * 1.2 + 1)^0.5 = 1.48 * 3.5 = 5.19. Another Pentagram increases this to 6.45 (a 1.26 increase instead of a 1.69 increase). The higher a character's base damage, the more effective damage ups will be for that character. Flat damage modifiers and special adjustments like Polyphemus or Sacred Heart happen after the main formula.

Character Modifier[]

The character base damage is defined by a base number and a multiplier.

Eve^†: 0.75 * 3.50 = 2.625
Jacob^‡: 1.00 * 3.5 - 0.75 = 2.75
Isaac, Magdalene, Samson, Lazarus, Eden, Lilith, The Lost, Apollyon, The Soul, Bethany: 1.00 * 3.50 = 3.50
???: 1.05 * 3.50 = 3.675
Esau^‡: 1.00 * 3.5 + 0.25 = 3.75
Keeper, Cain, and Lazarus Risen: 1.20 * 3.50 = 4.20
Judas: 1.35 * 3.50 = 4.725
Azazel: 1.50 * 3.50 = 5.25
The Forgotten: 1.50 * 3.50 = 5.25
Dark Judas: 2 * 3.50 = 7.00

^†: Whore of Babylon has the unique effect of increasing Eve's damage modifier from 0.75 to 1.00 when active. This does not apply to other characters, however.
^‡: Jacob and Esau have -0.75 and +0.25 flat damage respectively: their base damage, as far as the damage formula is considered, is still 3.5 with a 1.0 multiplier.

Damage Multipliers[]

Some items multiply damage rather than simply adding to it. Damage multipliers do not simply multiply the character's damage once; the damage stat is constantly recalculated and the damage multipliers are multiplied with the end result. This means that if a character starts with 3.50 damage and gets a 2x multiplier, their effective damage will be 3.5*2 = 7.00. If an item that grants +1 damage is picked up, the character's effective damage will be 3.5*(1*1.2+1)^0.5*2 = 3.5*(2.2)^0.5*2 = 3.5*1.48*2 = 10.38, and not 7.00 + 1.

Most damage multipliers stack; for example, Proptosis and Eve's Mascara both provide a 2x multiplier; picking up both will give a total multiplier of 4x. The exception to this is the 1.5x damage multipliers provided by Cricket's Head, Magic Mushroom, and the combination of Blood of the Martyr and The Book of Belial. These multipliers do not stack; for example, picking up both Cricket's Head and Magic Mushroom will result in an overall 1.5x multiplier rather than the expected 2.25x.

Reverse Formula[]

Consequently, the reverse formula to determine your damage bonuses from the displayed value is $\color {white}{\mathit {Bonus}}={\frac {1}{1.2}}\left[\left({\frac {{\mathit {EffectiveDamage}}/{\mathit {Multipliers}}-{\mathit {FlatDmgUps}}}{\mathit {CharBaseDmg}}}\right)^{2}-1\right]$ Multipliers is the product of all damage multipliers in effect.

Items that affect damage[]

Activated Items[]

Name	ID	Quote	Description	Quality
Razor Blade	5.100.126	Feel my pain	On use, takes one heart of health and grants +1.2 damage for the current room.	0
The Book of Belial	5.100.34	Temporary DMG up	+2 damage for the current room. Guarantees a Devil Room or Angel Room will be open after beating a boss while holding it. Increases the chance by 12.5%.	3
The Nail	5.100.83	Temporary demon form	Gives one Soul Heart half a Black Heart. For the current room; +0.7 damage, -0.18 speed, allows Isaac to break rocks and damage enemies by walking over them.	3
D8	5.100.406	Reroll stats	Re-rolls Isaac's damage, tears, range, and speed.	2
Dataminer	5.100.481	109	Displaces enemy sprites for the current room, randomly increases one stat and decreases another.	0
Potato Peeler	5.100.487	A pound of flesh	Removes a Heart Container, increases damage and range, and grants a Cube of Meat.	3
Void	5.100.477	Consume	Consumes all pedestal items in the room. Active items will have their effects added to Void, and passive items will grant random stat upgrades.	4
Berserk!	5.100.704	Rip and tear	Causes Isaac to go berserk for 5 seconds, greatly increasing his speed, tears, and damage, but restricting him to using a melee weapon instead of his tears. This item charges by dealing damage to enemies instead of clearing rooms.	3
Dark Arts	5.100.705	One with the shadows	Makes Isaac invulnerable and intangible for one second. When the effect ends, all enemies Isaac ran through take damage and Isaac temporarily gains +1 damage for each one.	2
Golden Razor	5.100.555	Pain from gain	Spends five coins to increase Isaac's damage by 1.2 for the current room.	2
Mega Mush	5.100.625	I'm a big boy now!	Gigantifies Isaac for 30 seconds, increasing damage and range while lowering tears, granting invulnerability, and allowing Isaac to crush enemies and obstacles he walks on. The effect persists between rooms.	4
Sulfur	5.100.556	Temporary demon form	Grants Brimstone for the current room.	2

Passive Items[]

Name	ID	Quote	Description	Quality
20/20	5.100.245	Double shot	Isaac fires two tears at once, one from each eye. 0.75x damage multiplier.	4
A Lump of Coal	5.100.132	My Xmas present	The more distance tears travel, the more damage they will do.	3
Abaddon	5.100.230	Evil + DMG up + fear shot	+1.5 damage, +0.2 speed. Removes all Red Heart containers, grants six Black Hearts, and adds a chance to shoot fear tears. +1.5 damage, +0.2 speed. Grants two Black Hearts, converts all Red Heart Containers into Black Hearts, and adds a chance to shoot fear tears.	4
Blood Clot	5.100.254	DMG + range up	Tears fired from the left eye have +1 flat damage, +5 range, and +0.5 tear height.	2
Blood of the Martyr	5.100.7	DMG up	Increases damage by 1, and turns Isaac's tears into blood tears.	3
Bloody Lust	5.100.157	RAGE!	Increases Isaac's damage whenever he takes damage, up to six times. The bonus resets when entering a new floor.	3
Brimstone	5.100.118	Blood laser barrage	Tears are replaced by a laser beam that pierces through all enemies and obstacles in its path and deals high damage. Can only be fired after a short charge-up period.	4
Capricorn	5.100.307	All stats up	Adds 1 Red Heart Container, gives +0.5 Damage, +0.1 Speed, +1.5 / +0.75 Range, and -1.0 Tear Delay, and gives 1 Bomb, Coin, and Key.	3
Cat-O-Nine-Tails	5.100.165	Shot speed + damage up	+1 damage, +0.23 shot speed.	3
Ceremonial Robes	5.100.216	DMG + evil up	Grants 3 Black Hearts, and +1 damage.	3
Champion Belt	5.100.208	DMG + challenge up	Increases damage, but also increases the chance of champion enemies appearing.	3
Chemical Peel	5.100.154	DMG up	Tears fired from the left eye have +2 flat damage.	1
Cricket's Head	5.100.4	DMG up	Increases Damage by 0.5, and increases damage multiplier by x1.5.	4
Dark Matter	5.100.259	DMG up + fear shot	+1 damage, adds a chance to shoot fear tears.	3
Death's Touch	5.100.237	Piercing shots + DMG up	+1.5 damage, -0.3 tears. Tears are replaced with large piercing scythes.	3
Eve's Mascara	5.100.310	DMG up, tears + shot speed down	Doubles damage, halves tears stat, and greatly reduces shot speed.	1
Experimental Treatment	5.100.240	Some stats up, some stats down	Randomly increases and decreases some of Isaac's stats. Increases four random stats and decreases the other two.	1
Godhead	5.100.331	God tears	Grants homing tears with a damaging halo. +0.5 damage, -0.3 tears, +1.2 range, -0.3 shot speed, +0.8 tear height.	4
Growth Hormones	5.100.70	Speed + DMG up	+1 damage, +0.4 speed. +1 damage, +0.2 speed.	3
Guillotine	5.100.206	DMG + tears up. An out-of-body experience!	Isaac's head is removed from his body and floats around him as an orbital. Gives +1 damage and grants -1 tear delay.	3
Ipecac	5.100.149	Explosive shots	Replaces tears with explosive and poisoning projectiles fired in an arc from the mouth.	4
Iron Bar	5.100.201	DMG up + concussive tears	Increases damage by 0.3 and adds a chance to shoot concussive tears, causing enemies to walk around randomly.	3
Jesus Juice	5.100.197	Damage + range up	+0.5 damage, +0.25 range, +0.5 tear height.	2
Magic Mushroom	5.100.12	All stats up!	Makes Isaac bigger. Adds one Red Heart container, +0.3 damage, x1.5 damage multiplier, +5.25 range, and +0.3 speed. Restores all health on pickup.	4
MEAT!	5.100.193	DMG + HP up	Grants one full Red Heart container, +0.3 damage.	2
Missing No.	5.100.258	Syntax error	Randomizes all passive items and stats upon pickup and at the start of each succeeding floor.	2
Odd Mushroom	5.100.121	HP + DMG up, speed down	Grants one empty Heart container, +0.3 damage, +0.25 range, +0.5 tear height, and -0.1 speed.	2
Odd Mushroom	5.100.120	Tears + speed up, DMG down	+1.7 tears, +0.3 speed, slightly reduces damage.	3
Pentagram	5.100.51	DMG up	+1 damage, increases Devil Room / Angel Room chance by 10%.	3
Polyphemus	5.100.169	Mega tears	Isaac fires huge tears that deal massive damage, but fire rate is greatly decreased. If a tear kills an enemy, it travels on with any leftover damage.	4
Proptosis	5.100.261	Short range mega tears	Tears start out massive with high damage, and then shrink down and become weaker over a short range.	4
Sacred Heart	5.100.182	Homing shots + DMG up	Grants homing tears, x2.3 damage multiplier, +1 flat damage, +4.125 range, +0.75 tear height, -0.4 tears, -0.25 shot speed, a red Heart Container and replenishes all Red Hearts.	4
SMB Super Fan	5.100.189	All stats up	+1 Red Heart container, +0.3 damage, +0.2 tears, +0.2 speed, +0.5 range, +1 tear height. Fully restores all red hearts.	3
Soy Milk	5.100.330	DMG down + tears way up	Tears are smaller and do much less damage, but fire in very rapid succession.	2
Steven	5.100.50	DMG up	Increases damage by 1.	3
Stigmata	5.100.138	DMG + HP up	Increases damage, and adds 1 heart container.	2
Synthoil	5.100.345	DMG + range up	+1 damage, +5.25 range, +0.5 tear height.	3
Technology 2	5.100.152	Extra laser	Decreases damage and replaces the tears fired from Isaac's right eye with a rapidly firing and piercing laser. Reduces the tears of Isaac's left eye; damage is unaffected.	2
The Halo	5.100.101	All stats up	Grants one full Red Heart container, +0.3 damage, +0.2 tears, +0.25 range, +0.3 speed, and +0.5 tear height.	2
The Mark	5.100.79	DMG + speed up	Grants one Soul Heart, +1 damage, and +0.2 speed.	3
The Pact	5.100.80	DMG + tears up	Grants two Soul Hearts, +0.5 damage, and +0.7 tears. Grants two Black Hearts, +0.5 damage, and +0.7 tears.	3
The Small Rock	5.100.90	DMG up	Increases damage by 1, increases tears by 0.2, and decreases speed by 0.2.	3
Whore of Babylon	5.100.122	Curse up	Grants +1.5 damage and +0.3 speed whenever Isaac has half a red heart or less (one red heart for Eve), ignoring any Soul or Black Hearts.	2
8 Inch Nails	5.100.359	Stick it to 'em!	+1.5 damage. Replaces Isaac's tears with nails, which have increased knockback.	3
Crown of Light	5.100.415	The untainted gain power	+2 soul hearts. While Isaac has no empty red hearts, grants 2x damage, +5.25 range, and -0.3 shot speed. Regardless of health, the crown deactivates for the current room when Isaac takes damage.	4
Dead Eye	5.100.373	Accuracy brings power!	Isaac's damage increases each time an enemy is hit. Damage is reset upon missing a shot.	3
Lusty Blood	5.100.411	Their blood brings rage!	Isaac's damage increases for the current room each time he kills an enemy.	3
Maw of the Void	5.100.399	Consume thy enemy!	Charged by firing for 2.5 seconds and when released, creates a black ring around Isaac that rapidly deals damage. +1 damage, the ring can cause enemies to drop Black Hearts.	4
Purity	5.100.407	Aura stat boost	Boosts one of Isaac's stats depending on the color of the aura around him. The aura disappears upon taking damage and reappears with a random color upon entering a new room. Red boosts damage, blue boosts tears, yellow boosts speed, and orange boosts range.	2
Adrenaline	5.100.493	Panic = power	Increases damage based on how many empty Red Heart containers Isaac has.	1
Bozo	5.100.513	Party time!	+0.1 flat damage, grants a Soul Heart. Enemies can randomly become briefly charmed or feared. Taking damage has a chance to spawn a rainbow poop.	2
Death's List	5.100.530	Just hope you're not next...	Grants a pickup or stat upgrade if all enemies in a room are killed in the order they are marked.	2
Dog Tooth	5.100.445	Bark at the moon!	+0.3 damage, +0.1 speed. Plays a howl or bark sound when entering a room with undiscovered Secret Rooms or Crawl Spaces.	1
Haemolacria	5.100.531	I'm seeing red...	Tears are now fired in an arc. Upon hitting the floor, an obstacle, or an enemy, they burst into many smaller tears in all directions. Increases tear delay.	2
Sulfuric Acid	5.100.463	Acid tears!	+0.3 damage. Adds a chance to fire acidic tears which can destroy obstacles.	2
Trisagion	5.100.533	Smite thy enemy	Damage down. Tears are replaced with piercing white blasts of light that can damage the same enemy multiple times.	2
Almond Milk	5.100.561	DMG down + tears up + you feel nutty	Quadruples fire rate, with x0.3 damage multiplier. Tears are given random worm trinket effects.	1
Binge Eater	5.100.664	All you can eat	+1 Red Heart Container and fully heals Isaac. Item pedestals cycle between their initial item and one of several food items, and picking up food items grants a temporary damage boost and a permanent boost to 2 stats (different for each one) in addition to their normal effects. Food items will also heal 2 additional Red Hearts when picked up.	3
Blood Oath	5.100.569	Bleed me dry	Stabs Isaac at the beginning of each floor, draining his red hearts. Increases damage and speed for the floor based on the amount drained.	2
Dogma	5.100.633	Ascended	Grants flight, +0.1 speed, +2 damage, and the Holy Mantle effect. Grants enough health to have 6 full hearts, if possible. Automatically given to Isaac after defeating Dogma.	0
Eye of the Occult	5.100.572	DMG up + range up + controlled tears	Isaac's tears are now controlled mid-flight with tear controls. Also increases damage and range, but decreases shot speed.	3
Heartbreak	5.100.694	Eternal sorrow	Grants 3 broken hearts and +0.25 damage for every broken heart Isaac has. Every otherwise fatal hit will add 2 more until Isaac has nothing but broken hearts.	3
Immaculate Heart	5.100.573	Halo of tears	Adds one Red Heart Container and fully restores health. x1.2 damage multiplier. Isaac will occasionally fire extra tears that orbit around him.	3
Red Stew	5.100.621	Full HP + temporary DMG up	Refills all heart containers. Grants an enormous damage boost that wears off over time.	0
Redemption	5.100.673	Deliver me from evil	Gives Isaac a soul heart and +1 damage if he goes into a Devil Room but doesn't take anything from it.	2
Sausage	5.100.669	All stats up	Adds a Red Heart Container, fully heals Isaac, and gives +0.2 Speed, +0.5 Damage, +0.5 Tears, +1.5 Range, +0.2 Shot Speed, and +1.0 Luck.	3
Stapler	5.100.708	DMG up	+1 damage. Prevents Isaac from firing tears from one eye, like Cain.	3
Terra	5.100.592	Born to rock	Replaces tears with rocks that deal variable damage, have increased knockback, and can destroy obstacles.	3

Trinkets[]

Name	ID	Quote	Description
Curved Horn	5.350.35	DMG up	Increases damage by 2.
Red Patch	5.350.40	Your rage grows	Grants a chance of increasing damage by 1.8 for the current room upon taking damage.
Samson's Lock	5.350.58	Your rage grows	1/15 chance to increase damage by 0.5 for the current room each time an enemy dies.
Black Feather	5.350.80	With darkness comes power	Increases Isaac's damage by 0.2 for each 'evil' item and trinket he possesses. Increases Isaac's damage by 0.5 each instead.
Cracked Crown	5.350.92	Stat booster	Decreases Isaac's tear delay by 20%, and improves the effectiveness of his other stat upgrades by ~33%. Improves the effectiveness of other stat upgrades by ~20%.
Dim Bulb	5.350.101	I think it's broken	Provides a boost to all stats when Isaac's active item is completely uncharged.
Vibrant Bulb	5.350.100	It needs power	Provides a boost to all stats when Isaac's active item is fully charged.

Other[]

In co-op, Rage Baby, Revenge Baby, and Belial Baby will occasionally briefly increase damage. Dark Baby will occasionally briefly increase all stats, including damage. Buddy Baby will occasionally briefly grant the Guillotine effect, which increases damage. Whore Baby will occasionally briefly grant the Whore of Babylon effect, which increases damage.
III - The Empress activates the Whore of Babylon effect for the current room, which increases damage.
XI - Strength activates the Magic Mushroom effect for the current room, which increases damage.
XV - The Devil activates The Book of Belial effect for the current room, which increases damage.
Black Rune consumes all pedestal items in the room and turns them into random stat upgrades. No effect on shop items.
Huge Growth increases damage, range, and Isaac's size for the current room.