Defense

Defense is a player statistic that determines how much damage can be absorbed per hit. On non-Expert Mode worlds, damage the player takes is reduced by half of their defense value, rounded up. In Expert Mode, damage the player takes is reduced by three-quarters of their defense value, rounded up. Defense can be increased by equipping armor and accessories, or temporarily boosted by various buffs. No attack can be reduced below 1 damage (with the exception of a player with an ally wearing the Paladin's Shield).

Some forms of damage are impossible to reduce through defense. Damage from health-draining Debuffs like Cursed Inferno, drowning in water, or colliding with a boulder are not reduced by defense.

Damage taken from lava can be reduced through defense.

Mechanics

Defense gives an arithmetic reduction in damage: i.e. damage is reduced by a fixed amount per hit (as opposed to a geometric damage reduction, which would reduce damage by a percentage).

Non-Expert Mode Formula

The formula is:

net damage = attack - (defense * 0.5)

For example:

• With 10 Defense, a 20 Damage attack is reduced by 5, resulting in 15 damage taken.
• With 21 Defense, a 20 Damage attack is reduced by 11, resulting in 9 damage taken.

Expert Mode Formula

In expert mode, the formula is:

net damage = attack - (defense * 0.75)

For example:

• With 20 Defense, a 40 Damage attack is reduced by 15, resulting in 25 damage taken.
• With 30 Defense, a 40 Damage attack is reduced by 23, resulting in 17 damage taken.

Note that in expert mode only the player's defense follows the formula. Enemies will still take the same amount of damage as in normal mode.

Enemies

Enemies have the same Defense mechanics as players. Monsters with high defense will take virtually no damage from low damage weapons (e.g. Fire Imps take 5 damage from the Minishark with Musket Balls). Accordingly, when fighting high defense monsters, high damage weapons are preferable.

Defense boosts

Here is a list of accessories, and their respective defense bonuses. A list of armor including defenses can be found on the armor page.

Item	Accessory Defense
Shackle	1
Cobalt Shield	1
Obsidian Skull	1
Shield of Cthulhu	2
Obsidian Shield	2
Moon Charm	3 (only during the night)
Moon Shell	3 (only during the night)
Moon Stone	4 (only during the night)
Sun Stone	4 (only during the day)
Celestial Stone	4
Ankh Shield	4
Paladin's Shield	6 (Absorbs 25% of damage done to players on your team Only active above 25% life)
Celestial Shell	4 (during the day) 7 (during the night)
Flesh Knuckles	7
Frozen Turtle Shell	0 until below 50% health when it reduces total damage by 25% 30 (When below 25% health)
Goblin Tinkerer's / random Modifiers	4 (Max per accessory)
Buff / Debuff	Temporary Defense
Well Fed	2
Dryad's Blessing (Buff)	8
Ironskin	8
Tipsy	Defense reduced by 4
Weak	Defense reduced by 4
Ichor (debuff)	Defense reduced by 20
Broken Armor	Defense reduced by half

Damage reduction boosts

Buff	Source	Damage reduction bonus
Solar Blaze	Solar armor	30%
Beetle Endurance	Beetle armor	15%/30%/45%
Paladin's Shield	Paladin's Shield	25% (Only active above 25% life)
Endurance	Endurance Potion	10%
Ice Barrier	Frozen Turtle Shell	0 / 25% (When below 50% health)
Warmth	Warmth Potion	30% (Reduces damage only from cold-themed enemies)
Item	Source	Damage reduction bonus
Worm Scarf	Treasure Bag (Eater of Worlds)	17%

Armor Penetration

Desktop-Only Content: This information (or parts of it) applies only to the desktop version of Terraria.

Armor penetration is a statistic that reduces the defense of the player's targets. For instance, a Pixie normally has 20 defense. If the player has 5 Armor Penetration, then the Pixie will be taken to have 15 defense instead.

Source	Armor penetration bonus
Shark Tooth Necklace	5
Sharpening Station	4 for Melee Weapons only

Notes

• The highest possible defense is 165 normally, and 173 in expert mode.
  • Chlorophyte Mask，Solar Flare Breastplate and Solar Flare Leggings or Vortex Leggings - 79 defense
  • Flesh Knuckles - 7 defense
  • Celestial Shell - 7 defense if worn at night
  • Paladin's Shield - 6 defense
  • Guarding with the Brand of the Inferno - 20 defense
  • Any other two accessories that give 4 defense at night - 8 defense
  • Warding modifiers on all accessories - 20(normal)/24(expert) defense
  • Ironskin buff - 8 defense
  • Well fed buff - 2 defense
  • The Dryad's Blessing grants an additional 8 defense.
  • Riding a Mechanical Cart at full speed gives an additional 7 defense (expert mode only, but can be imported to a normal world). - However, you cannot guard with the Brand of the Inferno while riding a Mechanical Cart.
  • Any sixth accessory that gives 4 defense at night, with a Warding prefix (expert mode only).
• The highest damage reduction is 87%.
  • Armor-based reductions are multiplicative.
    • Beetle Armor with shell - 45% reduction
  • Accessory- and potion-based reductions are additive.
    • Frozen Turtle Shell - 25% reduction
    • Worm Scarf - 17% reduction
    • Endurance Potion - 10% reduction
    • Paladin's Shield buff - 25% reduction

 (100%-45%) * (100%-(25%+17%+10%+25%)) = 12.7% damage taken = 87.3% damage reduction

Trivia

Although not possible in-game, if a piece of armor were to gain a prefix, it would apply the affects just like an accessory would; an example being a set of warding armor adding 12 defense.