What the result actually measures
The Nether is scaled 8 to 1 against the Overworld on the horizontal axes. Going in, X and Z are divided by 8 and rounded down; coming out, they are multiplied by 8. Y is not scaled.
Measurement boundary: The calculator places the coordinate. Whether two portals link also depends on the game finding an existing portal near that point before building a new one, and on terrain, height limits and the edition you play.
How to interpret the output
Rounding down, not to nearest
The game drops the fraction towards negative infinity, so −243 becomes −31 in the Nether, not −30. Calculators that round to the nearest block put a negative coordinate one block off.
Why portals mis-link
Two Overworld portals closer than eight times the Nether link distance can resolve to the same Nether portal. Spread them further apart, or build their Nether partners first at the exact calculated spots.
Troubleshooting unexpected results
The portal took me somewhere else
An existing portal near the destination wins over building a new one. Check for an older portal close to the calculated spot, or build the partner portal yourself first.
Y does not match
Height is not scaled. The game places or finds the portal at a safe height near the target, so build the partner at a comfortable Y and it will link on X and Z.
Frequently asked questions
How do I convert Overworld coordinates to the Nether?
Divide X and Z by 8 and round down. An Overworld portal at X 800, Z −240 belongs at X 100, Z −30 in the Nether.
Is Y divided by 8 too?
No. Only the horizontal X and Z are scaled; height stays the same scale in both dimensions.
Why round down?
Because that is what the game does with the fractional position. It matters for negative coordinates, where rounding to the nearest block lands one block away from where the game will look.
