Altitude



Altitude is a measurement of vertical distance, or distance along the Y-axis.

Definition
Altitude is defined as "the height of anything above a given planetary reference plane, especially above sea level on earth."

In Minecraft, altitude is commonly expressed as the number of block layers above the bottom of the game environment, which is layer zero (0). For instance, sea level is recognized as block layer 62, and clouds appear at layer 127.

Altitude may also be expressed as the bottom face of the block layer, the bottom most of which is at Y-coordinate 0, or Y=0. Sea level would appear at Y=63, and cloud level would appear at Y=128. The player can press to see the Y-coordinate of the top face of the block on which they are standing.

Features and effects by height

 * Largest height Minecraft can distinguish from infinity, Java's.
 * Above this height, players cannot move except using NBT editors.
 * Maximum height reachable by flying, the point where the datatype stops growing in steps of 0.5.
 * 4096: Maximum height reachable by /teleport or /tp.
 * 256: Top face of the highest block that can be placed.
 * 100-150: Clouds.
 * 128: Upper limit of Coal Ore generation.
 * 127: Full bedrock layer in the Nether.
 * 124-126: Partial bedrock layers in the Nether.
 * 80: Upper limit of Gold Ore generation in Badlands and variants.
 * 70: Upper limit of Slime spawn in Swamps.
 * 64: Upper limit of Iron Ore generation.
 * 63:Sea level. Players must be above this level for phantoms to spawn.
 * 50: Lower limit of Slime spawn in Swamps outside "slime chunks".
 * 40: Upper limit of Slime spawn in non-Swamp biomes in "slime chunks".
 * 32: Upper limit of Lapis Lazuli Ore, Emerald Ore and (in non-Badlands biomes) Gold Ore generation.
 * 16: Upper limit of Redstone Ore and Diamond Ore generation.
 * 1-4: Partial bedrock layers in Overworld.
 * 1-3: Partial bedrock layers in the Nether.
 * 0: Full bedrock layer in the Overworld and Nether.
 * 0: Top of the Void; bottom face of the lowest block that can be placed. Liquids stop flowing when they reach this point.
 * -64:Players below this height take void damage ( per $1/2$ second) and, if $$, even if in Creative mode. This damage can't be prevented or mitigated, but commands can provide enough regeneration to survive it. Non-player entities falling below this height despawn instantly.
 * -30,000,000: Players below this height are kicked with an "invalid move player packet received" error. This can be fixed through external programs.

Limits in Bedrock Edition
The top of the game environment is layer 255, and the top face of the highest block that can be placed is at Y=256.

$$, the player dies instantly if they fall below Y=-2, unless in Creative mode. In creative mode, the player can fall only into Y=-40,but can use to lower. The height limit for building blocks is Y=256.

Natural resources and altitude
Features in the landscape of the Overworld are found at different altitudes, as shown in the graph below. There is also an interactive chart.



Note that these charts utilize the logarithmic scale, which means a slight difference in the Y-coordinate represents a large change in the relative frequency of a block type.

Some observations:
 * Looking at water, the amount at layer 62 (sea level) is obvious. Moving down, the amount quickly decreases at layers 56 and 48, the usual depth of river and ocean biomes, respectively.
 * There are corresponding peaks in the amount of clay beneath them.
 * Between layers 33 and 12, most water is falling down sub-ocean ravines, spreading out on the lava-filled bottom at layer 10 and producing most of the naturally-occurring obsidian.
 * Ores and gravel (not shown) usually occur as a fixed percentage of the amount of stone (also not shown), tapering off at the ends of their allowed generation range.
 * This is why coal and iron follow parallel tracks between layers 5 and 60.
 * The one exception is lapis lazuli ore, which has a linear progression up to a peak at layers 13-14.

See the following table for a textual description of resources by altitude and tools needed to gather them.

Other naturally occurring features appear at different altitudes, but all of these features are random and appear only in conjunction with another block and the proper environment.

The Nether
A similar graph, showing the distribution of blocks unique to the Nether:



Trivia

 * The highest possible altitude the player can legitimately climb to is Y=256, although explosions, elytra launchers, piston slime block bounces, and Riptide tridents can all propel the player far beyond this limit.
 * $$, mushrooms can appear on the nether's bedrock ceiling.
 * Block generation and player construction below and above the build limits can only be achieved through mods, such as the OpenCubicChunks mod.