Fall Damage is taken when your character falls more than 25 blocks; you will take damage based on the additional number of blocks fallen, assuming the impact isn't arrested in some manner. Every block above 25 that is fallen means an additional 10 damage, minus defense. For example, if you fall 60 blocks with 0 defense, upon impact, you will take 350 damage. The highest amount of damage from falling, from Outer Space to The Underworld in a large world and with no armor or defense-increasing accessories, is 12,510 damage.
The Fall Damage Equation
$ 10 * (v - 25) - ||(d / 2)|| = f $
$ v $ = Blocks fallen prior to impact, values below 25 aren't valid.
$ d $ = Character defense
$ f $ = Fall damage
$ || $ Signifies that this should be rounded to the nearest whole number.
Example: I fall 50 blocks with a defense of 21:
$ 10 * (50 - 25) - ||21/2|| = f $
$ 10 * 25 - 11 = f $
$ 250 - 11 = f $
$ f = 239 $ damage from falling!
Canceling Fall Damage
The four main ways to stop falling damage are using environmental factors, slowing or halting the fall, bypassing the fall and equipping an accessory that negates fall damage.
Bypassing the fall involves environmental factors to negate falling damage which includes falling into water, lava or cobwebs. All of these slow your fall without registering a falling impact, resetting the 25 block minimum fall distance before damage takes place. Falling onto a different source of environmental damage (any of the fire-block types without fire protection, for example) will also reset the falling distance counter. Getting hit by an enemy does not cancel fall damage.
Fall Damage can be negated or mitigated (depending on the timing) by several factors:
- Double-jumping, i.e. with a Cloud in a Bottle
- Lifting off with Rocket Boots
- Being under the effect of a Featherfall Potion
- Reversing gravity with a Gravitation Potion
- Activating hover mode with a Hoverboard or a Flying Carpet before touching the ground.
- You can pour water down a hole and jump down straight away if it is a big drop - the water will slow your fall down.
Note that, although it visually slows your descent, being knocked back by a monster during the fall does not prevent falling damage.
If you use a Magic Mirror right before hitting the ground after falling, you will hit the ground, but warp at the same time. No "You were slain..." message will appear but you will still get a death message saying "<Playername> fell to their death." Afterwards, you will warp back to your spawn as if you died normally (you will not be revived if you attempt this on a hardcore character).
When falling, a way to avoid the damage is to carefully place a Cobweb on the nearest block to your fall. However, this rarely works, but may be worthwhile to attempt.
While wearing a full set of Necro Armor, the fall damage noise is changed to the same sound as when you hit skeleton type enemies.