Minecraft fall damage

Some very clever Minecraft players have encountered a strange phenomenon: There is something weird going on with much damage players or mobs take from falling down.

The Minecraft community's main source of truth, "the wiki", provides a formula for how fall damage works:

1 point (half a heart) for each block of fall distance after the third.

But this does not seem to be exactly what happens when players try to fall and measure the results.

Formula vs. measured player damage

According to the formula a 23 block fall should kill a player, but does not! The formula isn't wrong though, there is simply something slighty more complicated happening.

Imagine a falling anvil. Let's say it takes that anvil exactly 2 seconds to touch the ground. A standard movie camera which captures 25 images a second would grab 50 images of the event. However, there were really infinitely many other potential images in-between what the camera caught. The anvil didn't move through the air in 50 separate jerks, it came down in a constant fluid motion.

Staggered vs fluid motion

Minecraft works in a sort-of simliar way. 20 times a second the game performs a "tick" where it does most of the work of moving things around. Also to see if objects are colliding with each other (such as an anvil and the ground).

What the game does for falling objects every tick, is to:

1. Increase their speed towards a maximum speed-limit.
2. Move them by their speed downwards.
3. Check if something has hit the ground, and if it needs to go splat!

Like our camera recording, Minecraft does only work with moments of time. Unlike the anvil in the above example, the objects in Minecraft do only move in separate jerks. It just happens so fast that our human brains can't tell the difference.

One second of falling

But it also means that things are less exact.

Keep in mind that speed can be more than 1 block at a time, and things can't move through the ground: When something does go splat!, the game needs to find the closest block to where that thing was before it hit the ground. Last "ticks'" number. That number will be in fractions of a block and will be moved to the nearest block.

So, because:

1. The object is falling in steps.
2. The distance is made equal (rounded) to a block size.
3. Last "tick's" number is used.

When determining the damage value, sometimes these added up make more of a difference than you would expect! 💥