Loaded Chunks

Loaded Chunks/Simulated Chunks

Loaded Chunks also known as simulated chunks are the chunks that anything can normally process in. These chunks only occur around a player or created with the use of /tickingarea or Add-ons. These chunks are what players will spend their time interacting with a majority of the time.

Buffer Chunks

Around every loaded chunk is a buffer of unloaded chunks this is to improve load times and general stability of the game.

Loaded Area Size

The size of the area of loaded chunks around a player is dependent on the simulation distance setting in the world settings and it comes in four different sizes 4 chunks, 6 chunks, 8 chunks, and 12 chunks. These sizes are not radii as you may be inclined to believe but instead follow taxicab geometry, going from each corner of the central chunk containing the player. 

(blue: sim 4, green: sim 6, yellow/orange: sim 8, pink/red: sim 10, purple: sim 12)

Functions

Chunks that are loaded/simulated are able to process anything you will find in normal gameplay such as: 

• Entity AI/Events
• block ticking
• random ticks
• Entity states

It is important to note that events can happen outside of these loaded chunks. See unloaded chunks for more information.