Binding of Isaac: Rebirth Wiki

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

Effective Damage[]

The formula for damage is:


  • 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 Curved Horn or Ipecac Ipecac), and
  • EffectiveDmg = the approximate damage that can be expected per tear, or per 'tick' when using Brimstone Brimstone or Technology 2 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 Polyphemus or Sacred Heart Sacred Heart happen after the main formula.

Character Modifier[]

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

: Whore of Babylon 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, Removed in Repentance Proptosis Proptosis and Eve's Mascara 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 Cricket's Head, Magic Mushroom Magic Mushroom, and the combination of Blood of the Martyr Blood of the Martyr and The Book of Belial 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 Multipliers is the product of all damage multipliers in effect.

Items that affect damage[]

Activated Items[]

Name ID Icon Quote Description Added in Repentance Quality
Razor Blade 5.100.126
Razor Blade
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
The Book of Belial
3 rooms
Temporary DMG up Removed in Afterbirth +2 damage for the current room. Passively guarantees a Devil Room Devil Room or Angel Room Angel Room will appear while held.
Added in Afterbirth +2 damage for the current room. Passively increases the chance of finding a Devil Room Devil Room or Angel Room Angel Room while held.
The Nail 5.100.83
The Nail
6 rooms
Temporary demon form Removed in Repentance Gives one Soul Heart Soul Heart. For the current room; +0.7 damage, -0.18 speed, Isaac breaks rocks and deals contact damage.
Added in Repentance Gives half a Black Heart Black Heart. For the current room; +2 damage, -0.18 speed, Isaac breaks rocks and deals contact damage.
Added in Afterbirth D8 5.100.406
4 rooms
Reroll stats Re-rolls Isaac's damage, tears, range, and speed. 2
Added in Afterbirth † Dataminer 5.100.481
4 rooms
109 Displaces enemy sprites for the current room, randomly increases one stat and decreases another. 0
Added in Afterbirth † Potato Peeler 5.100.487
Potato Peeler
A pound of flesh Removes a Heart Container, increases damage and range, and grants a Cube of Meat Cube of Meat. 2
Added in Afterbirth † Void 5.100.477
6 rooms
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
Added in Repentance Berserk! 5.100.704
With damage dealt
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
Added in Repentance Golden Razor 5.100.555
Golden Razor
Pain from gain Spends five coins to increase Isaac's damage by 1.2 for the current room. 1
Added in Repentance Mega Mush 5.100.625
Mega Mush
12 rooms
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
Added in Repentance Sulfur 5.100.556
3 rooms
Temporary demon form Grants Brimstone Brimstone for the current room. 2

Passive Items[]

Name ID Icon Quote Description Added in Repentance Quality
20/20 5.100.245 20/20 Double shot Isaac fires two tears at once, one from each eye.
Added in Repentance 0.75x damage multiplier.
A Lump of Coal 5.100.132 A Lump of Coal My Xmas present The more distance tears travel, the more damage they will do. 3
Abaddon 5.100.230 Abaddon Evil + DMG up + fear shot Removed in Repentance +1.5 damage, +0.2 speed. Removes all Red Heart containers, grants six Black Hearts, and adds a chance to shoot fear tears.
Added in Repentance +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.
Blood Clot 5.100.254 Blood Clot 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 Blood of the Martyr DMG up Increases damage by 1, and turns Isaac's tears into blood tears. 3
Bloody Lust 5.100.157 Bloody Lust 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 Brimstone 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 Capricorn All stats up Removed in Repentance Adds 1 Red Heart Container, gives +0.5 Damage, +0.1 Speed, +1.5 Range, and -1.0 Tear Delay, and gives 1 Bomb, Coin, and Key.
Added in Repentance Adds 1 Red Heart Container, gives +0.5 Damage, +0.1 Speed, +0.75 Range, and -1.0 Tear Delay, and gives 1 Bomb, Coin, and Key.
Cat-O-Nine-Tails 5.100.165 Cat-O-Nine-Tails Shot speed + damage up +1 damage, +0.23 shot speed. 3
Ceremonial Robes 5.100.216 Ceremonial Robes DMG + evil up Grants 3 Black Heart Black Hearts, and +1 damage. 3
Champion Belt 5.100.208 Champion Belt DMG + challenge up Increases damage, but also increases the chance of champion enemies appearing. 3
Chemical Peel 5.100.154 Chemical Peel DMG up Tears fired from the left eye have +2 flat damage. 2
Cricket's Head 5.100.4 Cricket's Head DMG up Increases Damage by 0.5, and increases damage multiplier by x1.5. 4
Dark Matter 5.100.259 Dark Matter DMG up + fear shot +1 damage, adds a chance to shoot fear tears. 3
Death's Touch 5.100.237 Death's Touch Piercing shots + DMG up +1.5 damage, -0.3 tears. Tears are replaced with large piercing scythes. 3
Eve's Mascara 5.100.310 Eve's Mascara DMG up, tears + shot speed down Doubles damage, halves tears stat, and greatly reduces shot speed. 2
Experimental Treatment 5.100.240 Experimental Treatment Some stats up, some stats down Removed in Afterbirth † Randomly increases and decreases some of Isaac's stats.
Added in Afterbirth † Increases four random stats and decreases the other two.
Godhead 5.100.331 Godhead God tears Removed in Repentance Grants homing tears with a damaging halo. +0.5 Damage, -0.3 Tears -0.3 Shot Speed, +0.8 Tear Height, and +1.2 Range.
Added in Repentance Grants homing tears with a damaging halo. +0.5 Damage, -0.3 Tears -0.3 Shot Speed, and +0.8 Tear Height.
Growth Hormones 5.100.70 Growth Hormones Speed + DMG up Removed in Repentance +1 damage, +0.4 speed.
Added in Repentance +1 damage, +0.2 speed.
Guillotine 5.100.206 Guillotine 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. 2
Ipecac 5.100.149 Ipecac Explosive shots Replaces tears with explosive and poisoning projectiles fired in an arc from the mouth. 4
Iron Bar 5.100.201 Iron Bar DMG up + concussive tears Increases damage by 0.3 and adds a chance to shoot concussive tears, causing enemies to walk around randomly. 2
Jesus Juice 5.100.197 Jesus Juice Damage + range up +0.5 damage, +0.25 range, +0.5 tear height. 2
Libra 5.100.304 Libra You feel balanced Gives 6 coins, 6 bombs, and 6 keys and balances out all attributes. 1
Magic Mushroom 5.100.12 Magic Mushroom All stats up! Makes Isaac bigger. Adds one Red Heart Container, +0.3 Damage, x1.5 damage multiplier, Removed in Repentance +5.25 / Added in Repentance +1.5 Range, and +0.3 Speed, and restores all Health. 4
MEAT! 5.100.193 MEAT! DMG + HP up Grants one full Red Heart container, +0.3 damage. 2
Missing No. 5.100.258 Missing No. Syntax error Randomizes all passive items and stats upon pickup and at the start of each succeeding floor. 1
Odd Mushroom 5.100.121 Odd Mushroom 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 Odd Mushroom Tears + speed up, DMG down +1.7 tears, +0.3 speed, slightly reduces damage. 2
Pentagram 5.100.51 Pentagram DMG up +1 damage, increases Devil Room / Angel Room chance by 10%. 3
Polyphemus 5.100.169 Polyphemus 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 Proptosis 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 Sacred Heart Homing shots + DMG up Removed in Repentance Adds a Red Heart Container. Grants homing tears, a x2.3 Damage multiplier, +1 flat Damage, -0.4 Tears, -0.25 Shot Speed, and +4.125 Range.
Added in Repentance Adds a Red Heart Container. Grants homing tears, a x2.3 Damage multiplier, +1 flat Damage, -0.4 Tears, and -0.25 Shot Speed.
SMB Super Fan 5.100.189 SMB Super Fan 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 Soy Milk DMG down + tears way up Tears are smaller and do much less damage, but fire in very rapid succession. 2
Steven 5.100.50 Steven DMG up Increases damage by 1. 3
Stigmata 5.100.138 Stigmata DMG + HP up +0.3 damage, grants one full Red Heart container. Added in Repentance Heals 1 additional Red Heart Red Heart. 2
Synthoil 5.100.345 Synthoil DMG + range up +1 damage, +5.25 range, +0.5 tear height. 3
Technology 2 5.100.152 Technology 2 Extra laser Replaces the tears fired from Isaac's right eye with a rapid-firing low damage piercing laser. Removed in Repentance Damage down. 2
The Halo 5.100.101 The Halo 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 The Mark DMG + speed up Removed in Repentance Grants one Soul Heart Soul Heart, +1 damage, and +0.2 speed.
Added in Repentance Grants one Black Heart Black Heart, +1 damage, and +0.2 speed.
The Pact 5.100.80 The Pact DMG + tears up Removed in Repentance Grants two Soul Heart Soul Hearts, +0.5 damage, and +0.7 tears.
Added in Repentance Grants two Black Heart Black Hearts, +0.5 damage, and +0.7 tears.
The Small Rock 5.100.90 The Small Rock DMG up + speed down +1 damage, +0.2 tears, -0.2 speed. 3
Whore of Babylon 5.100.122 Whore of Babylon Curse up Grants +1.5 Damage and +0.3 Speed whenever Isaac has half a Red Heart or less. 2
Added in Afterbirth 8 Inch Nails 5.100.359 8 Inch Nails Stick it to 'em! +1.5 damage. Replaces Isaac's tears with nails, which have increased knockback. 3
Added in Afterbirth Crown of Light 5.100.415 Crown of Light 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
Added in Afterbirth Dead Eye 5.100.373 Dead Eye Accuracy brings power! Isaac's damage increases each time an enemy is hit. Damage is reset upon missing a shot. 3
Added in Afterbirth Lusty Blood 5.100.411 Lusty Blood Their blood brings rage! Isaac's damage increases for the current room each time he kills an enemy. 3
Added in Afterbirth Maw of the Void 5.100.399 Maw of the Void Consume thy enemy! Charged by firing for 2.5 seconds and when released, creates a black ring around Isaac that rapidly deals damage. Removed in Repentance +1 damage, the ring can cause enemies to drop Black Hearts. 4
Added in Afterbirth Purity 5.100.407 Purity 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. 3
Added in Afterbirth † Adrenaline 5.100.493 Adrenaline Panic = power Increases damage based on how many empty Red Heart containers Isaac has. 1
Added in Afterbirth † Bozo 5.100.513 Bozo 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
Added in Afterbirth † Death's List 5.100.530 Death's List 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
Added in Afterbirth † Dog Tooth 5.100.445 Dog Tooth Bark at the moon! +0.3 damage, +0.1 speed. Plays a howl or bark sound when entering a room with undiscovered Secret Room Secret Rooms or Crawl Space Crawl Spaces. 1
Added in Afterbirth † Haemolacria 5.100.531 Haemolacria 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. 3
Added in Afterbirth † Sulfuric Acid 5.100.463 Sulfuric Acid Acid tears! +0.3 damage. Adds a chance to fire acidic tears which can destroy obstacles. 2
Added in Afterbirth † Trisagion 5.100.533 Trisagion Smite thy enemy Damage down. Tears are replaced with piercing white blasts of light that can damage the same enemy multiple times. 2
Added in Repentance Almond Milk 5.100.561 Almond Milk DMG down + tears up + you feel nutty Quadruples fire rate, with x0.3 damage multiplier. Tears are given random worm trinket effects. 1
Added in Repentance Binge Eater 5.100.664 Binge Eater All you can eat +1 Red Heart Container and fully heals Isaac. Item pedestals also offer a random food item. Picking up a food item temporarily grants +3.6 damage and permanently boosts 2 stats. 4
Added in Repentance Blood Oath 5.100.569 Blood Oath 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
Added in Repentance Dogma 5.100.633 Dogma Ascended Grants flight, +0.1 speed, +2 damage, and the Holy Mantle Holy Mantle effect. Grants enough health to have 6 full hearts, if possible. Automatically given to Isaac after defeating Dogma. 0
Added in Repentance Eye of the Occult 5.100.572 Eye of the Occult 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
Added in Repentance Glass Eye 5.100.730 Glass Eye DMG + luck up +0.75 damage, +1 luck. 3
Added in Repentance Heartbreak 5.100.694 Heartbreak 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
Added in Repentance Immaculate Heart 5.100.573 Immaculate Heart 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
Added in Repentance Keeper's Sack 5.100.716 Keeper's Sack Spending power Gives range, speed, or damage when buying things from a shop. Also spawns three coins and a Key Key on pickup. 3
Added in Repentance Mom's Ring 5.100.732 Mom's Ring DMG up +1 Damage. Drops a random Rune or Soul Stone upon pickup. 3
Added in Repentance Red Stew 5.100.621 Red Stew Full HP + temporary DMG up Refills all heart containers. Grants an enormous damage boost that wears off over time. 2
Added in Repentance Redemption 5.100.673 Redemption Deliver me from evil If Isaac enters a Devil Room Devil Room, but leaves without taking/opening anything in it (including Black Heart Black Hearts, etc.), he gets +1 Damage and a Soul Heart Soul Heart at the start of the next floor. 2
Added in Repentance Sausage 5.100.669 Sausage 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. Increases the chance of encountering a Devil Room Devil Room, Angel Room Angel Room, and/or Planetarium Planetarium each by 6.9%. 3
Added in Repentance Stapler 5.100.708 Stapler DMG up +1 Damage. Prevents Isaac from firing tears from his left eye, like Cain Cain. 3
Added in Repentance Stye 5.100.731 Stye DMG + range up Tears fired from Isaac's right eye have +28% Damage, +7 Range, and -0.3 Shot Speed. 2
Added in Repentance Terra 5.100.592 Terra Born to rock +1 Damage. Replaces tears with rocks that deal variable damage, have increased knockback, and can destroy obstacles. 3


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