Defense

Defense is the number that determines how much damage can be absorbed per hit. Damage the player takes is reduced by half their defense value, rounded up.

Defense can be increased by equipping armor and accessories, or temporarily boosted by consuming Ironskin Potions and Bowls of Soup

Mechanics

Defense (or Defense Rating) gives an arithmetic reduction in damage: i.e. reduces damage by a fixed amount per hit (as opposed to a geometric damage reduction, which reduces damage by a percentage).

Formula

The formula is:

Damage Reduction = ROUND_UP(Defense * 0.5)

For example, with 10 (or 9) Defense, a 20 Damage attack is reduced by 5, to 15 Damage.

Strategy

Because of this, high Defense is particularly effective against low damage attacks, which can be reduced almost completely, but not as effective against high damage attacks, where the reduction is just flat. This also means that added defense gets increasingly more important. A jump from 10 to 20 defense has smaller benefits on average than a jump from 30 to 40 defense.

Monsters

Monsters 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.

Armor and Accessory Defense

Here is a list of armors, accessories, and their respective defense bonuses, including any applicable set bonuses. As of the 1.1 update the highest possible defense bonus obtainable is 85. Hallowed armor gives 50 defense, you can then equip an Obsidian Shield (+2), Obsidian Skull (+1), Cobalt Shield (+1), Moon Charm (+1 during a full moon) Shackle (+1) to provide a defense of 56. If all these accessories have the warding attribute, that provides an additional 20 defense, totaling 76 defense. Ironskin and bowl of soup then give an additional 9 giving 85 total defense.

Item/Set	Total Defense
Copper armor	6
Iron armor	9
Silver armor	13
Gold armor	16
Meteor armor	10
Shadow armor	19
Necro armor	16
Jungle armor	13
Molten armor	25
Cobalt armor with Hat	17
Cobalt armor with Helmet	26
Cobalt armor with Mask	19
Mythril armor with Hood	24
Mythril armor with Helmet	37
Mythril armor with Hat	27
Adamantite armor with Headgear	28
Adamantite armor with Helmet	46
Adamantite armor with Mask	32
Hallowed armor with Headgear	31
Hallowed armor with Helmet	35
Hallowed armor with Mask	50
Cobalt Shield	1
Obsidian Skull	1
Obsidian Shield	2
Shackle	1
Bucket	1
Goggles	1
Wizard Hat	2
Mining Helmet	1
Diving Helmet	2
Ironskin Potion	8 (for 5 minutes)
Bowl of Soup	1 (for 10 minutes)
Ale	-4 (for 2 minutes)
Goblin Tinkerer's / random Modifiers	4 (Max per accessory) 20 total

Notes

• No attack can be reduced to less than 1 Damage.
• Defense applies to all forms of damage, including, but not limited to fall damage, gravity influenced blocks (sand and silt), Lava, spikes, meteorite, and hellstone.
• Modifiers on accessories can increase the defense of an accessory by up to 4 points.