Minecraft wiki entry for Tick, associated text: In Java Edition, chunks with loading type of entity ticking (see Chunk#Level and load type) and with horizontal distance between its center and a player (not in spectator mode) less than 128 blocks are ticked on every game tick. A few things should be noted here: first, the chunk should be loaded as an entity-ticking chunk. Second, if the chunk receives chunk tick, even if some blocks in the chunk are out of the 128-block radius, they can receive random tick as normal. Third, because 128 blocks is the horizontal distance, the player's position along the y-axis does not matter.