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Nether portal calculator

Convert Overworld ↔ Nether coordinates using the 1:8 ratio so your portals actually link up, instead of generating a stray second portal next door.

↓ ×⅛ / ×8
Nether X0
Nether Y—
Nether Z0

Tip: build within a couple of blocks of these exact coordinates — Minecraft links to the nearest valid portal within a 128-block search radius, or generates a brand new one if it doesn't find yours.

🔒 Runs entirely in your browser — nothing is sent anywhere.

Why coordinates need converting

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The Nether is 8x smaller

Every block in the Nether corresponds to 8 blocks in the Overworld — a highway system, so travelling 1000 blocks in the Nether covers 8000 Overworld blocks.

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Precise linking

Portals link to the nearest valid portal within a 128-block search radius of the converted coordinate — being off by a lot creates a duplicate portal instead of linking.

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Height limits

The Nether's buildable height is 0-127. This tool flags when a converted Y falls outside that range.

Nether portal calculator FAQ

Why is the ratio 1:8?

The Nether is compressed 8x relative to the Overworld — moving 1 block in the Nether covers the same ground as moving 8 blocks in the Overworld. Overworld coordinates divide by 8 to get Nether coordinates; Nether coordinates multiply by 8 to get Overworld coordinates.

Why don't my portals link up?

Minecraft links to the nearest existing valid portal within a 128-block search radius of the exact converted coordinate. If nothing is found in range, a brand new portal is generated instead — build as close as possible to the converted X/Z to avoid this.

What if the converted Y is above the Nether roof?

The Nether's playable height is 0-127. If your Overworld Y converts outside that range, the portal generates at the nearest valid Y instead — this tool flags that for you.