Luck

Luck affects a variety of chance-based effects and is represented by a 3-leaf clover.

Effects of Luck
Luck influences many different elements:
 * Room drops: For calculating room drops, luck is capped between 0 and 10, with higher luck not only resulting in higher amounts of drops but also higher quality drops such as chests.
 * Room drop rates are otherwise identical in Normal and Hard game modes, but Hard mode removes 65% of heart-type drops, replacing them with nothing.
 * For Jacob and Esau, the room drop rate depends on the total luck the 2 characters have.
 * In Repentance Hard mode heart-type drops' drop rate is the same as Normal mode.
 * Tear effect chance: The chance of shooting tears with status effects becomes more likely as Luck goes up. This scales up to 100% chance per tear in most cases with enough Luck.
 * Most of the status inflicting effects require high Luck to activate on every tear.
 * Since these effects persist on the enemies for a set amount of time regardless of the Tears stat, a fast rate of fire is often enough to affect an enemy indefinitely.
 * Certain tear effect chances scale linearly with luck, while others scale exponentially with luck, meaning that it can take a lot of luck to notice a significant increase in activation rates.


 * Tear items affected by Luck are:
 * (Tears cause fear) - 100% at 85 Luck
 * (Razor tears) - 100% at 14 Luck
 * (Tears slow enemies) - 100% at 18 Luck
 * (Fire produced along with tear) - 100% at 11 Luck
 * (Poison tears) - 100% at 12 Luck
 * (Tears cause fear) - 100% at 20 Luck
 * (Needle tears) - 100% at 15 Luck
 * (Eye tears) - Slight increase with high Luck
 * (Chance that tears explode) - 100% at 13 Luck
 * (Fire produced along with tear) - 100% at 11 Luck
 * (Tears inflict effect) - Maximizes at 50% at 9 Luck
 * (Tears confuse enemies) - 100% at 27 Luck
 * (Tears cause enemy to become magnetized) - 100% at 10 Luck
 * (Instant death tears) - Maximizes at 20% with 15 Luck
 * (4-way tears) - 100% at 7 Luck
 * (Tears petrify enemies) - Maximizes at 50% with less than 20 Luck
 * (Forwards and backwards tears) - 100% at 2 Luck
 * (Tears charm enemies) - 100% at 27 Luck
 * (Tears cause fear) - 100% at 85 Luck
 * (Spawn blue spiders while shooting) - 100% at 10 Luck
 * (Egg tears) - Maximizes at 50% with around 20 Luck
 * (Tears slow enemies) - 100% at 15 Luck
 * (Teeth instead of tears) - 100% at 9 Luck


 * Trinkets affected by Luck are:
 * Black Tooth (Poisonous double damage tear) - 100% at 32 Luck
 * Cain's Eye ( effect) - 100% at 3 Luck
 * Cartridge ( effect when hit) - 100% at 38 Luck
 * Eve's Bird Foot (Spawn a dead bird on killing an enemy) - 100% at 8 Luck
 * Isaac's Fork (Heal half a heart on clearing a room) - 100% at 18 Luck
 * Jawbreaker (Chance for tooth shot dealing x3.2 damage) - 100% at 9 Luck
 * A Missing Page ( effect) - Maximizes at 50% with 50-60 Luck
 * Ouroboros Worm (Chance to shoot homing tears) - 100% at 9 Luck
 * Pinky Eye (Poison tears) - 100% at 18 Luck
 * Push Pin (Spectral + Piercing tears) - 100% at 18 Luck
 * Red Patch (+1.8 Damage Up on taking damage) - 100% at 8 Luck
 * Samson's Lock (Chance for +0.5 Damage Up on killing an enemy) - 100% at 10 Luck


 * Other items affected by Luck include:
 * : Higher luck increases the rate of freezing enemies and their shots.
 * : The Celtic Cross grants its invulnerability more often with higher Luck, topping out at 100% at 27 Luck.
 * : The Soul Heart/Black Heart drop chance upon taking damage increases with higher Luck, topping out at 50% at 22 Luck.
 * : Poops generated by Isaac's actions have a chance to turn into Golden Poop, starting at 10% with 0 Luck up to 100% at 18 Luck.
 * : Higher luck results in a lower chance of getting or.
 * : The Red Heart drop chance when you take a hit increases with higher Luck, topping out at 50% at 29 Luck.
 * : The shield activation chance increases with Luck, topping out at 100% at 10 Luck.

However, Luck doesn't affect:
 * Fortune teller,, shell game, slot machine: Their chance of giving a consumable don't increase with Luck. Only increases the winning chances with these machines.
 * The activation chance of:, , , , , , , (for I AM ERROR or black market teleports),  (for Crawl Spaces),  (as its effects are predetermined depending on which floor it's used on), and.
 * Content from Chests, Pots, Mushrooms, Skulls, Blue Fires, Purple Fires, Devil rooms, and angel rooms.
 * Beggars, Devil beggars, key masters, and bomb bums aren't affected by Luck.

Other

 * "Luck Up" pills increase luck by 1, and "Luck Down" pills decrease luck by 1.
 * Putting a coin in the Donation Machine has a small chance to increase luck by 1.
 * Lucky pennies increase luck by 1.
 * In co-op, Green Baby will occasionally briefly increase luck by 2. Dark Baby will occasionally briefly increase all stats, including luck.