Nether portals that link where you want them to — the 1:8 rule in practice
Portals do not pair by coordinates alone. Here is the search box the game actually checks, why your portal keeps connecting to the wrong one, and how to force a clean pair.
The maths everyone knows is Overworld ÷ 8 = Nether. The part that trips people up is what happens after that division: the game does not build a portal at those exact coordinates. It searches.
What the game actually does
When you step into a portal, Minecraft converts your coordinates, then looks for an existing portal inside a search box around the target:
- 129×129 blocks horizontally, centred on the converted position
- the full height of the destination dimension
If it finds one, you come out there — even if that portal is 60 blocks from where you wanted. Only if the box is empty does it build a new portal.
That single rule explains almost every "my portals are linked wrong" report.
Why two Overworld portals share one Nether portal
Two Overworld portals 400 blocks apart convert to Nether positions 50 blocks apart. Fifty is inside 129, so both find the same Nether portal and both come out there. From the Overworld they feel unrelated; in the Nether they are neighbours.
Rule of thumb: Overworld portals need to be more than 1,024 blocks apart to be guaranteed separate Nether-side destinations (1024 ÷ 8 = 128, just outside the box).
Forcing a clean pair
- Build the Overworld portal, note X and Z.
- Divide both by 8, round toward zero. That is your Nether target.
- Go to the Nether and build the portal there manually, at those coordinates, before
ever using the Overworld one.
- Light it. Now walk through the Overworld portal — it finds yours and links.
Building the second side by hand is the whole trick. Let the game generate it and you inherit whatever it finds first.
Y matters less than you think
Vertical position is not part of the 1:8 conversion — Y is carried across unchanged and then clamped to the destination's buildable range. Two portals stacked at Y=30 and Y=100 in the Nether are both inside the same horizontal box, so they compete.
Roof travel
Nether ceiling highways work because 1 block up there equals 8 in the Overworld. A 1,000 block walk on the roof moves you 8,000 blocks at home. The portal search box is what decides where you land, so space your roof portals at least 129 blocks apart or they will collapse into each other.
Put your real coordinates into the Nether Portal Calculator — it converts both directions and draws the actual 129-block search box on a to-scale map, so you can see whether two portals will fight before you build them.