Tools
Server chunk calculator
Work out how much of the world your server keeps: chunks per player at your view-distance and simulation-distance, for everyone online — and how many chunks and region files a world with a border of a given radius holds.
Chunk calculator
160 blocks in each direction
160 blocks in each direction
An upper bound: players close together share chunks, so there are fewer.
view-distance is a radius in chunks, and (2r+1)² is the square around the player. Since 1.18 the game loads a circle, so the real number is lower.
Per minecraft.wiki: entities update in a square of min(2s+1, 63), blocks and redstone in a ring of chunks wider, min(2s+3, 65).
World pre-generation
The border is square: /worldborder set takes the diameter, Chunky the radius. One region is 32×32 chunks.
/worldborder center 0 0
/worldborder set 10000
chunky center 0 0
chunky radius 5000
chunky startChunks and server load
A chunk is a 16×16-block column of the world. view-distance is how many chunks in each direction the server sends a player; simulation-distance is how many of them are alive — mobs move, redstone runs, crops grow. Both default to 10 and accept 3 to 32.
Every player keeps their own area loaded, so load grows with your player count. When a server can't keep up, a common step is lowering simulation-distance while keeping view-distance higher: the world is visible far away but only simulated near players. The spark profiler shows where ticks are actually lost.
Generating new chunks is one of the heaviest jobs a server does. That's why worlds are bordered in advance and pre-generated with the Chunky plugin: the calculator shows how many chunks and region files that means. A region file r.X.Z.mca holds 32×32 chunks.
DGuard uses 0.03% of one core on the main thread: its checks run on network threads and don't take tick time.
Read in the knowledge base
FAQ
How many chunks load around a player?
At view-distance 10, at most 21×21 = 441 chunks; since 1.18 the area is round, so fewer in practice. At simulation-distance 10, entities update in a 21×21 square.
What's the difference between view-distance and simulation-distance?
view-distance is how far a player sees the world; simulation-distance is how far the world is alive — mobs move, redstone runs. The second can be lower than the first.
How much disk space will a pre-generated world take?
It depends on the world: the calculator gives the chunk count, but chunk size on disk varies. Pre-generate a small radius, check the size of the region folder and scale from there.
Does /worldborder set take a radius or a diameter?
A diameter: /worldborder set 10000 is 5000 blocks from the centre in each direction. In Chunky that's a radius of 5000.
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