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Knockback is a basic mechanism in Terraria whereby players and enemies are repelled in the opposite direction of an attack. Most weapons and environment objects that cause damage also cause knockback, to varying degrees. Some enemies are immune to knockback, particularly bosses and other enemies that travel through blocks, like worms and Man Eaters. Some enemies also have varying degrees of knockback resistance.

The player can become immune to knockback by equipping the Cobalt Shield, Paladin's Shield, or any of their upgrades, or by grappling on any surface using any hook. Wearing the full Gladiator armor(Desktop, Console and Mobile versions) set also grants the player knockback immunity.

Player-inflicted knockback can be increased by various modifiers, the Titan Glove accessory and its upgrades, the Titan Potion, and the Shroomite and Vortex armors'(Desktop, Console and Mobile versions) stealth effects. Critical hits increase the inflicted knockback by 40%. Enemies that are afflicted with Cursed Inferno receive 10% more knockback.

Knockback values

The knockback inflicted by an item is usually displayed in its tooltip. The exact values are not displayed, they are grouped into the following categories instead:

Value In-game text
0 No knockback
≤ 1.5 Extremely weak knockback
≤ 3 Very weak knockback
≤ 4 Weak knockback
≤ 6 Average knockback
≤ 7 Strong knockback
≤ 9 Very strong knockback
≤ 11 Extremely strong knockback
> 11 Insane knockback


The following steps are taken when an enemy is struck with a weapon that inflicts knockback.[1]

First, calculating knockback resistance:

knockBack = knockBack * (1 - enemyKnockbackResist)

Then multiplying knockback by 110% if the target is suffering from Cursed Inferno:

if cursedInferno then knockBack = knockBack * 1.1

Then applying cap to it if needed:[2]

if knockBack > 8.0 then knockBack = 8 + (knockBack - 8.0) * 0.9
if knockBack > 10.0 then knockBack = 10 + (knockBack - 10.0) * 0.8
if knockBack > 12.0 then knockBack = 12 + (knockBack - 12.0) * 0.7
if knockBack > 14.0 then knockBack = 14 + (knockBack - 14.0) * 0.6
if knockBack > 16.0 then knockBack = 16

Then multiplying knockback by 140% if it is a critical hit:

if isCrit then knockBack = knockBack * 1.4

Finally, the computed knockback value is converted to speed. There are differing multipliers depending on whether the hit is more than 10% / 15% of the enemy's maximum health, and there is a special 1.5× multiplier to vertical speed for Snow Flinxes.

Immune enemies


Weapons inflicting the most knockback

The Slap Hand has the highest listed base knockback value (20), followed by the Shadow Jousting Lance(Desktop, Console and Mobile versions) (14), Hallowed Jousting Lance(Desktop, Console and Mobile versions) (13), Jousting Lance(Desktop, Console and Mobile versions) (12), Golem Fist (12), Morning Star(Desktop, Console and Mobile versions) (11), Celebration Mk2(Desktop, Console and Mobile versions) (10), and the Thorns Potion, which retaliates with 10 knockback when its effect triggers.

The Jousting Lances have the potential to inflict even more knockback, though, as their knockback depends on the player's speed.

The weapons with the potential for the highest knockback in the game are the Gray and Orange Zapinator. Their laser beams have a chance to multiply their knockback by 9 upon hitting an enemy. With the base knockback of 6, they can achieve knockback values of 54 after one hit (1/20 (5%) chance), 486 after two subsequent hits (1/400 (0.25%) chance), etc. The highest possible knockback value of a laser beam (with unmodified base knockback) is 28,697,814, achieved after seven hits where knockback is increased (the beam disappears after the eighth hit). However, the odds of this are incredibly low at 1 in 1,280,000,000.

The listed base knockback values of all weapons can be seen at the list of weapons. Remember that knockback is capped at 16 (22.4 for critical hits), after calculating the enemy's knockback resistance.


  1. Information taken from the Desktop version Desktop source code, method StrikeNPC() in Terraria.NPC.cs. There may be inaccuracies, as the current Desktop version Desktop version is
  2. This is written properly, it follows the steps in order so that a Slap Hand against a target that is not alight with Cursed Inferno and does not critically hit ends up at 14.9168 knockback, having been reduced 4 times, barring other enemy-specific modifiers.