minecraft-java-edition
In Minecraft, you can only build up to a certain height limit (which is something around 256). However, if a player uses mods/hacks to go above the limit (Or simply goes into Creative Mode), then they can go above the height limit.
How high is the player height limit in Minecraft? Is there even a limit to it? I've tried testing this myself, but my thumb started hurting when I reached Y= 1000.
As of 1.2.1, the build limit doubled from 128 to 256, while cloud height appears to not have moved. This means you actually have more room to build above the clouds (about 128) than you do between sea level and the clouds (about 64).
As of Beta 1.8, clouds now appear above the build limit. Notch also claims to have made the level height more consistent throughout the code, which leads me to assume that the clouds will always remain above the build limit regardless of that actual number.
I tested this by building the tallest possible pillar in creative mode. Standing on top of it (picture 1) puts your head just above the clouds. Flying beside it (picture 2) confirms that the clouds are above the build limit. Standing on a 1 meter shorter pillar puts the clouds just above your head, meaning that the clouds are about 1.5 meters above the build limit.
My bukkit server still has the kick-on-speedhack parameter in the bukkit.yml file, but that might not be evidence of it being deprecated.
Add: kick-on-speedhack: false
under settings: anyway to give it a go if you haven't already.
Best Answer
There is no limit to a player's height. The Y coordinate is tracked with the same size of variable as the X and Z, so you can go as infinitely* high as you can travel infinitely* far. There is no extra limitation placed on player height, so the only limitation is how to get there.
With cheats on, you can use
/tpto experiment with how high you can go, and you can see your position by toggling on the debug screen with F3.* Not actually infinite, but it takes many days of real time to walk that far.