How do I convert Minecraft block coordinates to chunk coordinates?

Divide the block X coordinate by 16 and round down (floor) to get the chunk X. Do the same for Z. For example, block X=100 is in chunk X=6 (floor(100/16) = 6). Block X=-1 is in chunk X=-1 (floor(-1/16) = -1). Y coordinates use the same formula to get the chunk section (sub-chunk): chunk section Y = floor(blockY / 16).

How do I find the region file (.mca) for a set of block coordinates?

First convert block coords to chunk coords (divide by 16, floor). Then divide the chunk coordinates by 32 and floor again to get the region coordinates. The file name is r.{regionX}.{regionZ}.mca. For example, block (550, 64, -900) → chunk (34, ?, -57) → region (1, -2) → r.1.-2.mca. Region files live in the world/region/ folder for the Overworld, world/DIM-1/region/ for the Nether, and world/DIM1/region/ for the End.

What is a chunk section in Minecraft?

A chunk section (also called a sub-chunk) is a 16×16×16 block cube. A full chunk column is made up of multiple chunk sections stacked vertically. In Minecraft 1.18 and later, the world extends from Y=-64 to Y=320, giving 24 chunk sections per chunk column (section Y from -4 to 19). Before 1.18, the world ran from Y=0 to Y=255, giving 16 sections (0 to 15). Chunk sections matter for world editors like MCA Selector and WorldEdit, and for understanding region file storage.

How do Nether portal coordinates work in Minecraft?

The Nether is exactly one-eighth the horizontal scale of the Overworld. To find where to build the corresponding Nether portal for an Overworld location, divide both X and Z by 8 (round down). To go the other way — finding where an Overworld portal should be to link to a Nether location — multiply the Nether X and Z by 8. Y coordinates are independent and do not need to match, though portals typically form between Y=48 and Y=70 in the Nether.

What is the chunk index in a region file?

Each .mca region file stores up to 1024 chunks in a fixed header table. The table index for a chunk is calculated as: (localChunkZ × 32) + localChunkX, where localChunkX = chunkX mod 32 and localChunkZ = chunkZ mod 32 (both adjusted to be non-negative). The index ranges from 0 to 1023. This matters when inspecting or repairing region files manually with tools like NBTExplorer or custom scripts.

What changed about coordinates in Minecraft 1.18?

Minecraft 1.18 (Caves & Cliffs Part 2) expanded the world height. The Overworld now extends from Y=-64 at the bottom to Y=320 at the top, a total of 384 blocks tall instead of 256. This means chunk section Y indices now run from -4 (the section containing Y=-64 to Y=-49) to 19 (the section containing Y=304 to Y=319). Old coordinates at Y=0 are still valid; the new space was added below Y=0 (down to bedrock at Y=-64) and above Y=256.

Where are Minecraft region files stored?

Region files are stored in the world save folder under different sub-directories depending on the dimension: Overworld → .minecraft/saves/{worldname}/region/, Nether → .minecraft/saves/{worldname}/DIM-1/region/, The End → .minecraft/saves/{worldname}/DIM1/region/. On a server the base path is the server's root folder. Each .mca file covers a 512×512 block (32×32 chunk) area of terrain.

What are biome coordinates in Minecraft 1.18+?

Since 1.18, biomes are stored in a three-dimensional 4×4×4 block grid rather than the old 1×256×1 column system. To find a block's biome cell coordinates, divide each of X, Y, and Z by 4 and floor. All blocks within the same 4×4×4 cell share one biome. This matters for biome finders, structure generation, and commands like /locatebiome.

How do I use coordinates with WorldEdit or MCA Selector?

WorldEdit uses block coordinates directly (the same values you see in the F3 screen). You can set positions with //pos1 and //pos2 or with //chunk to select the entire chunk you are standing in. MCA Selector works in chunk coordinates — enter chunk X and Z to select or delete chunks. Use this calculator to convert from the block coordinates you know to the chunk or region coordinates those tools expect.

Tools · Coordinates

Minecraft Coordinate Calculator

Convert any block coordinate (the X Y Z from your F3 screen) to its corresponding chunk section, region file, Nether portal position, and biome cell — all at once, live, bidirectionally. Edit any field and the rest update instantly.

Block ↔ Chunk ↔ Region ↔ Nether — fully bidirectionalJava Edition · Bedrock Edition · 1.18+ world height

Block Coordinates

F3 debug screen values

East +

Up +

South +

0, 64, 0/tp @s 0 64 0

Chunk Section

16×16×16 blocks

−4 to 19 (1.18+)

Local block (X Y Z)0 0 0

Section origin block0, 64, 0

Horizontal centre8, 64, 8

Region File

512×512 blocks

File namer.0.0.mca

Local chunk (X, Z)0, 0

Chunk index in file#0 of 1024

Region origin block0, ?, 0

r.0.0.mca

Nether Portal Coordinates

Overworld → Nether

Divide X and Z by 8 to find where to build the Nether portal.

0, 64, 0

/execute in minecraft:the_nether run tp @s 0 64 0

Nether → Overworld

Multiply X and Z by 8 to find the Overworld exit portal location.

0, 64, 0

Blocks to Chunk Section Wall

East (+ X)15 blocks

West (− X)0 blocks

South (+ Z)15 blocks

North (− Z)0 blocks

Up (+ Y)15 blocks

Down (− Y)0 blocks

Biome Coordinates

Since 1.18 biomes are sampled on a 4×4×4 block grid. Two blocks in the same biome cell are guaranteed to share a biome.

Biome cell X0

Biome cell Y16

Biome cell Z0

Biome cell origin block X0

Biome cell origin block Y64

Biome cell origin block Z0

Copy as Command

Teleport (Java)

/tp @s 0 64 0

Teleport (Bedrock)

/tp @s 0 64 0

Setblock at coords

/setblock 0 64 0 stone

Fill (chunk origin → this)

/fill 0 64 0 0 64 0 air

Nether portal (Overworld → Nether)

/execute in minecraft:the_nether run tp @s 0 64 0

Minecraft's four coordinate systems explained

Minecraft organises its world into nested layers. Understanding which layer you're working in saves a lot of confusion when using world editors, teleport commands, or just trying to meet a friend at exactly the right portal.

Block coordinates

The numbers you see on the F3 debug screen. X runs east (+) and west (−), Z runs south (+) and north (−), Y is altitude (up +). Every placeable block in the game occupies exactly one integer coordinate triplet. This is the coordinate system used by /tp, /setblock, /fill, and everything else players interact with directly.

Chunk sections (sub-chunks)

Chunks are the columns the game uses for loading and ticking. Each chunk is 16 blocks wide (X) by 16 blocks deep (Z) and spans the full world height. Internally, every chunk is divided into vertical chunk sections — 16×16×16 cubes. In Minecraft 1.18+ the world spans Y=−64 to Y=320, so there are 24 chunk sections per column (section Y from −4 to 19). Before 1.18, it was 16 sections covering Y=0 to Y=255.

Chunk coordinates are derived from block coordinates by floor-dividing by 16. Block X=−1 is in chunk X=−1 (not chunk X=0), because floor(−1/16) = −1. This "floor division" is why naive division in many calculators gives wrong results for negative coordinates.

Region files (.mca)

Minecraft groups 32×32 chunks (512×512 blocks) into a single Anvil format file with the extension .mca. The file name encodes the region's position: r.X.Z.mca. Region X = floor(chunkX / 32), Region Z = floor(chunkZ / 32). Inside each region file, chunks are indexed in a 1024-entry header table using the formula (localChunkZ × 32) + localChunkX.

Dimension	Region folder path
Overworld	saves/{world}/region/
Nether	saves/{world}/DIM-1/region/
The End	saves/{world}/DIM1/region/

Nether coordinates

The Nether map is 1/8th the horizontal scale of the Overworld. One block of horizontal travel in the Nether equals eight blocks in the Overworld. To link portals correctly, the Nether portal must be at exactly Overworld X ÷ 8 and Overworld Z ÷ 8. If the coordinates don't match, Minecraft creates a new portal rather than linking to the existing one — leading to the classic "portal loop" problem that wastes obsidian and confuses players.

Practical uses for this calculator

Fixing portal links

Portal A in the Overworld links to a random Nether location. Enter the Overworld coords, read off the Nether equivalent, and build or move your Nether portal to that position.

Finding a region file for MCA Selector

MCA Selector and NBTExplorer work with region files. Enter your block coordinates here to instantly get the file name (e.g. r.2.-3.mca) and the chunk index within it.

WorldEdit chunk selection

WorldEdit's //chunk selects the chunk you're standing in. Enter your target block coords here, read the chunk section origin, teleport there, then run //chunk to select it.

Chunk border visualisation

The "blocks to chunk wall" distances tell you exactly how far you are from each chunk border — useful for placing farms that must not overlap chunk boundaries, or for debugging mob spawning and entity processing issues.

Biome hunting and /locatebiome

The biome cell coordinate tells you the 4×4×4 grid cell your block sits in. Once you have a seed-based biome finder giving you biome cell coordinates, convert them here to the exact block coordinates you need to teleport to.

Calculating spawn distances

The Overworld spawn is at or near 0, 0. Enter a location to see its chunk — useful for checking whether a structure is within spawn chunk range (roughly ±8 chunks from 0,0 are always loaded on a vanilla server).

Minecraft 1.18 world height changes

The 1.18 Caves & Cliffs Part 2 update is the most significant coordinate change in Minecraft's history. The build height doubled and the floor dropped below zero:

Property	Pre-1.18 (1.17 and older)	1.18 and later
Minimum Y	0	−64
Maximum Y	255	320
Total height (blocks)	256	384
Chunk sections per column	16 (Y 0–15)	24 (Y −4 to 19)
Bedrock floor	Y=0 to Y=4	Y=−64 to Y=−60
Sea level	Y=62	Y=62 (unchanged)

X and Z coordinates were not affected. If you are working with a world that predates 1.18, the chunk section Y field will never be negative — all valid blocks were between Y=0 and Y=255.

Frequently asked questions

How do I convert block coordinates to chunk coordinates?

Divide the block X (and Z) by 16 and floor the result. The key is floor, not round — block X=−1 is in chunk X=−1, not chunk X=0, because floor(−1/16) = −1. This tool handles negative coordinates correctly.

How do I find the region file name for a location?

Enter your block coordinates above and read the "File name" field in the Region section. The formula is: region X = floor(floor(blockX/16) / 32), region Z = floor(floor(blockZ/16) / 32), file = r.{regionX}.{regionZ}.mca.

Why are my portals not linking correctly?

Portal linking requires the Nether-side portal to be within 8 blocks (in Nether coordinates) of the calculated target position. Enter your Overworld block coordinates, read the "Overworld → Nether" target, and make sure your Nether portal is within an 8-block radius of that point. If two portals compete, Minecraft picks the closest one.

What is a chunk section and why does it matter?

A chunk section is a 16×16×16 cube — the unit of storage inside a region file. Knowing the chunk section Y value matters for world editors that operate on section level (like NBT editors that target specific sub-chunk data) and for performance analysis (how many non-empty sections are loaded).

How do I use this with MCA Selector?

MCA Selector lets you select and delete chunks by region. Enter your block coordinates here, copy the region file name, open MCA Selector, navigate to that region, and locate the chunk using the displayed chunk X and Z values.

Where can I find servers to play on?

Browse thousands of Java and Bedrock servers on the Minecraft server list or explore server tags visually in the Server Cloud.