Binding of Isaac: Rebirth Wiki
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Damage Stat Icon 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. 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:

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 HornCurved Horn or Collectible Ipecac iconIpecac), and
  • EffectiveDmg = the approximate damage that can be expected per tear, or per 'tick' when using Collectible Brimstone iconBrimstone or Collectible Technology 2 iconTechnology 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.

: 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.

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, Collectible Proptosis iconProptosis and Collectible Eve's Mascara iconEve'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 Collectible Cricket's Head iconCricket's Head, Collectible Magic Mushroom iconMagic Mushroom, and the combination of Collectible Blood of the Martyr iconBlood of the Martyr and Collectible The Book of Belial iconThe 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 the damage multipliers in effect, including the character base multiplier, equal to 1 if there are none.

Items that affect damage

Activated Items

Name ID Icon Quote Description (in Repentance) Quality
Razor Blade 5.100.126
Razor Blade
Unlimited
Feel my pain Takes one Red HeartHeart of health and grants +1.2 damage for the current room. (in Repentance) Repeated uses in the same room only take half a heart. 0
The Book of Belial 5.100.34
The Book of Belial
3 rooms
Temporary DMG up (in Rebirth) +2 damage for the current room. Passively guarantees a Devil RoomDevil Room or Angel RoomAngel Room will appear while held.
(except in Rebirth) +2 damage for the current room. Passively increases the chance of finding a Devil RoomDevil Room or Angel RoomAngel Room while held.
2
The Nail 5.100.83
The Nail
6 rooms
Temporary demon form (except in Repentance) Gives one Soul HeartSoul Heart. For the current room; +0.7 damage, -0.18 speed, Isaac breaks rocks and deals contact damage.
(in Repentance) Gives half a Black HeartBlack Heart. For the current room; +2 damage, -0.18 speed, Isaac breaks rocks and deals contact damage.
2
(except in Rebirth) D8 5.100.406
D8
4 rooms
Reroll stats Re-rolls Isaac's damage, tears, range, and speed. 2
(in Afterbirth † and Repentance) Dataminer 5.100.481
Dataminer
4 rooms
109 Displaces enemy sprites for the current room, randomly increases one stat and decreases another. 0
(in Afterbirth † and Repentance) Potato Peeler 5.100.487
Potato Peeler
Unlimited
A pound of flesh Removes a Heart Container, increases damage and range, and grants a Collectible Cube of Meat iconCube of Meat. 2
(in Afterbirth † and Repentance) Void 5.100.477
Void
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
(in Repentance) Golden Razor 5.100.555
Golden Razor
Unlimited
Pain from gain Spends five PennyPennies to increase Isaac's damage by 1.2 for the current room. 1
(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
(in Repentance) Sulfur 5.100.556
Sulfur
3 rooms
Temporary demon form Grants Collectible Brimstone iconBrimstone for the current room. 3

Passive Items

Name ID Icon Quote Description (in Repentance) Quality
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 (except in Repentance) +1.5 damage, +0.2 speed. Removes all Red Heart containers, grants six Black HeartBlack Hearts, and adds a chance to shoot fear tears.
(in Repentance) +1.5 damage, +0.2 speed. Grants two Black HeartBlack Hearts, converts all Red Heart Containers into Black Hearts, and adds a chance to shoot fear tears.
3
Blood Clot 5.100.254 Blood Clot DMG + range up (except in Repentance)Tears fired from the left eye have +1 flat damage, +5 range, and +0.5 tear falling speed.
(in Repentance)Tears fired from the left eye have +1 flat damage and +2.75 range.
2
Blood of the Martyr 5.100.7 Blood of the Martyr DMG up +1 damage. Isaac shoots 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. 2
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 (except 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 BombBomb, PennyPenny, and KeyKey.
(in Repentance) Adds 1 Red Heart Container, gives +0.5 Damage, +0.1 Speed, +0.75 Range, and +0.5 Fire Rate, and gives 1 BombBomb, PennyPenny, and KeyKey.
3
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 HeartBlack Hearts, and +1 damage. 3
Champion Belt 5.100.208 Champion Belt DMG + challenge up +1 damage. Increases the chance of champion enemies appearing by 15%. 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 (except in Repentance) Doubles damage, halves tears stat, and greatly reduces shot speed.
(in Repentance) Doubles damage, 0.66x tears multiplier, and greatly reduces shot speed.
3
Experimental Treatment 5.100.240 Experimental Treatment Some stats up, some stats down (in Rebirth and Afterbirth) Randomly increases and decreases some of Isaac's stats.
(in Afterbirth † and Repentance) Increases four random stats and decreases the other two.
1
Godhead 5.100.331 Godhead God tears (except in Repentance) Grants homing tears with a damaging halo. +0.5 Damage, -0.3 Tears -0.3 Shot Speed, +0.8 Tear Falling Speed, and +1.2 Range.
(in Repentance) Grants homing tears with a damaging halo. +0.5 Damage, -0.3 Tears, and -0.3 Shot Speed.
4
Growth Hormones 5.100.70 Growth Hormones Speed + DMG up (except in Repentance) +1 damage, +0.4 speed.
(in Repentance) +1 damage, +0.2 speed.
3
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. (except in Repentance) Gives +1 damage and grants -1 tear delay. (in Repentance) Gives +1 damage and grants +0.5 fire rate. 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 +0.3 damage. Adds a chance to shoot concussive tears, causing enemies to walk around randomly. 2
Jesus Juice 5.100.197 Jesus Juice Damage + range up (except in Repentance) +0.5 damage, +0.25 range, +0.5 tear falling speed.
(in Repentance) +0.5 damage, +1.5 range.
2
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, (except in Repentance) +5.25 / (in Repentance) +2.5 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. (in Repentance) Heals 1 additional Red HeartRed Heart 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. 0
Odd Mushroom 5.100.121 Odd Mushroom HP + DMG up, speed down (except in Repentance) Grants one empty Heart container, +0.3 damage, +0.25 range, +0.5 tear falling speed, and -0.1 speed.
(in Repentance) Grants one full Heart container, +1 damage, +1.5 range, and -0.2 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 RoomDevil Room / Angel RoomAngel 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. 3
Sacred Heart 5.100.182 Sacred Heart Homing shots + DMG up (except 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.
(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.
4
SMB Super Fan 5.100.189 SMB Super Fan All stats up (except in Repentance) +1 Red Heart container, +0.3 damage, +0.2 tears, +0.2 speed, +0.5 range, +1 tear falling speed. Fully restores all red hearts.
(in Repentance) +1 Red Heart container, +0.3 damage, +0.2 tears, +0.2 speed, +2.5 range. 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 +1 damage. 3
Stigmata 5.100.138 Stigmata DMG + HP up +0.3 damage, grants one full Red Heart container. (in Repentance) Heals 1 additional Red HeartRed Heart. 2
Synthoil 5.100.345 Synthoil DMG + range up (except in Repentance) +1 damage, +5.25 range, +0.5 tear falling speed.
(in Repentance) +1 damage, +2.5 range.
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. (except in Repentance) Damage down. 2
The Halo 5.100.101 The Halo All stats up (except in Repentance) Grants one full Red Heart container, +0.3 damage, +0.2 tears, +0.25 range, +0.3 speed, and +0.5 tear falling speed.
(in Repentance) Grants one full Red Heart container, +0.3 damage, +0.2 tears, +1.5 range, and +0.3 speed. Heals 1 additional Red HeartRed Heart.
2
The Mark 5.100.79 The Mark DMG + speed up (except in Repentance) Grants one Soul HeartSoul Heart, +1 damage, and +0.2 speed.
(in Repentance) Grants one Black HeartBlack Heart, +1 damage, and +0.2 speed.
3
The Pact 5.100.80 The Pact DMG + tears up (except in Repentance) Grants two Soul HeartSoul Hearts, +0.5 damage, and +0.7 tears.
(in Repentance) Grants two Black HeartBlack Hearts, +0.5 damage, and +0.7 tears.
3
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 a Half Red HeartHalf Red Heart or less. 2
(except in Rebirth) 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
(except in Rebirth) Crown Of Light 5.100.415 Crown Of Light The untainted gain power +2 Soul HeartSoul Hearts. While Isaac has no empty red hearts, grants 2x damage, increased range, and -0.3 shot speed. Regardless of health, the crown deactivates for the current room when Isaac takes damage. 4
(except in Rebirth) 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
(except in Rebirth) 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
(except in Rebirth) 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. (except in Repentance) +1 damage, the ring can cause enemies to drop Black HeartBlack Hearts. 3
(except in Rebirth) 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
(in Afterbirth † and Repentance) Adrenaline 5.100.493 Adrenaline Panic = power Increases damage based on how many empty Red Heart containers Isaac has. 2
(in Afterbirth † and Repentance) Bozo 5.100.513 Bozo Party time! +0.1 flat damage, grants a Soul HeartSoul Heart. Enemies can randomly become briefly charmed or feared. Taking damage has a chance to spawn a Rainbow PoopRainbow Poop. 2
(in Afterbirth † and Repentance) 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
(in Afterbirth † and Repentance) 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 RoomSecret Rooms or Crawl SpaceCrawl Spaces. 2
(in Afterbirth † and Repentance) 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. 4
(in Afterbirth † and Repentance) Sulfuric Acid 5.100.463 Sulfuric Acid Acid tears! +0.3 damage. Adds a chance to fire acidic tears which can destroy obstacles and open doors. 2
(in Afterbirth † and Repentance) Trisagion 5.100.533 Trisagion Smite thy enemy Tears are replaced with piercing white blasts of light that deal less damage but can damage the same enemy multiple times. 3
(in Repentance) Almond Milk 5.100.561 Almond Milk DMG down + tears up + you feel nutty Quadruples fire rate, with x0.3 damage multiplier. Each tear is a given random effect that alters its movement. 1
(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
(in Repentance) Blood Oath 5.100.569 Blood Oath Bleed me dry Stabs Isaac at the beginning of each floor, draining his Red HeartRed Hearts. Increases damage and speed for the floor based on the amount drained. 1
(in Repentance) Dogma 5.100.633 Dogma Ascended Grants flight, +2 damage, and increases speed to 1.1. Grants enough health to have 6 full hearts, if possible. Grants the Collectible Holy Mantle iconHoly Mantle effect for the room it was obtained in. Automatically given to Isaac after defeating Dogma. 3
(in Repentance) Eye of the Occult 5.100.572 Eye of the Occult DMG up + range up + controlled tears +1 damage, +2 range, -0.16 shot speed. Isaac's tears can be controlled mid-flight with tear controls. 3
(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
(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
(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
(in Repentance) Redemption 5.100.673 Redemption Deliver me from evil If Isaac enters a Devil RoomDevil Room, but leaves without taking/opening anything in it (including Black HeartBlack Hearts, etc.), he gets +1 Damage and a Soul HeartSoul Heart at the start of the next floor. 2
(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, +2.5 Range, +0.2 Shot Speed, and +1.0 Luck. Increases the chance of encountering a Devil RoomDevil Room, Angel RoomAngel Room, and/or PlanetariumPlanetarium each by 6.9%. 3
(in Repentance) Stapler 5.100.708 Stapler DMG up +1 Damage. Prevents Isaac from firing tears from his left eye, like Character Cain iconCain. 3
(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

Trinkets

Name ID Icon Quote Description
Curved Horn 5.350.35 Curved Horn DMG up +2 flat damage.
Red Patch 5.350.40 Red Patch Your rage grows Grants a chance to gain +1.8 damage for the current room upon taking damage.
Samson's Lock 5.350.58 Samson's Lock Your rage grows 1/15 chance to gain +0.5 damage for the current room each time an enemy dies.
(except in Rebirth) Black Feather 5.350.80 Black Feather With darkness comes power Increases Isaac's Damage for each 'evil' item or trinket he possesses.
(in Afterbirth † and Repentance) Cracked Crown 5.350.92 Cracked Crown Stat booster (except in Repentance) Decreases Isaac's tear delay by 20%, and improves the effectiveness of his other stat upgrades by 33%.
(in Repentance) Improves the effectiveness of stat upgrades by 20%.
(in Afterbirth † and Repentance) 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.
(in Afterbirth † and Repentance) Vibrant Bulb 5.350.100 Vibrant Bulb It needs power Provides a boost to all stats when Isaac's active item is fully charged.

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