How to convert Nether coordinates
One block in the Nether equals eight blocks in the Overworld. From the Overworld to the Nether you divide X and Z by 8; on the way back you multiply them by 8. The height Y is not converted. Overworld X 800, Z −240 becomes Nether X 100, Z −30.
Why does my portal come out in the wrong place?
When you step through a portal, the game converts your position and looks for a portal there: in the Nether within 16 blocks in every direction, in the Overworld within 128 blocks. It picks the closest portal, and height counts too. If someone else’s portal is closer than yours, that is where you end up. If it finds none, it builds a new one – often in an awkward spot.
How to build a portal network without mix-ups
- Stand in your Overworld portal and read the coordinates with F3 (“Block” in Java Edition).
- Convert them above and build the Nether portal exactly there, ideally at a similar height.
- Add both portals to the list below. A green tick means the two are linked both ways.
- Do the same for every further portal. If two Nether portals sit close together, one can steal the other’s link – the list shows it right away.