Nether Portal Calculator

What is a Nether portal calculator?

A Nether portal calculator turns a position in the Overworld into the matching position in the Nether, and back. The two dimensions are on different scales: one block in the Nether stands for 8 blocks in the Overworld on the X and Z axes. Build your second portal at the converted spot and the game connects the two.

The conversion is the easy half. The hard half is linking, because the game does not remember which portal you built as a pair. Every time you step through, it searches the other dimension for the closest portal and sends you there. This tool does both: it converts, and it runs that same search on the list of portals you give it.

How do you use the calculator?

1. Pick your edition. Java and Bedrock search for portals differently, so the results depend on it.
2. Get your coordinates. Stand where the portal is (or will be) and read them from the game, or paste the F3 line or a /tp command into the paste box.
3. Read the result. Pick Overworld to Nether or Nether to Overworld. The other side shows where to build, the math behind it, and the commands to go there.
4. Check the link. Press "Add both portals to the link checker", then add your other portals. Every portal should show a green "Two-way" badge.
5. Fix what it flags. When a portal leads somewhere else, the checker tells you where to build its partner. "Add partner" puts that spot in the list so you can confirm the fix before you build it.

How do Nether coordinates work, and why is it 8 to 1?

Each dimension has a coordinate scale. The Overworld's is 1 and the Nether's is 8 (it is the coordinate_scale value in the Nether's dimension type). When an entity goes through a portal, the game multiplies its X and Z by the ratio of the two scales: 1/8 going into the Nether, 8 coming out. That is why the Nether works as a fast travel network. Walk 100 blocks in the Nether and you have covered 800 blocks of Overworld.

The ratio is the same in Java and Bedrock. A spot at X 1000, Z 1000 in the Nether matches X 8000, Z 8000 in the Overworld.

How do you calculate Nether coordinates by hand?

Divide the Overworld X and Z by 8 and round down. Rounding down means toward the more negative number, which is where most mistakes happen: -100 ÷ 8 = -12.5, and the game turns that into -13, not -12. Going the other way, multiply the Nether X and Z by 8. No rounding is needed for whole numbers, but the game uses your exact position, so standing anywhere inside Nether block 12 aims it at Overworld X 96 to 103.

A calculator that just cuts off the decimals gets every negative row in that table wrong by one block. One block is usually enough to matter in the Nether, where the search area is small.

What happens to the Y coordinate?

Nothing. Height is never scaled, so you arrive at the same Y you left from, as long as there is a portal there. Y still matters for linking, because the game measures the distance to each portal in three dimensions. A portal straight above the target but 40 blocks higher counts as 40 blocks away, and loses to one 10 blocks to the side at the same height.

The Nether is also shorter than the Overworld. It has a bedrock floor at Y 0 to 4, a bedrock roof at Y 123 to 127 and a lava sea up to Y 31. Java lets you build above the roof up to Y 255. Bedrock's Nether stops at Y 127. Portals the game builds by itself in the Nether always sit under the roof, and when it has to force one onto a platform, it puts it between Y 70 and 118.

How does the game choose which portal you come out of?

When you step through a portal and the wait ends (4 seconds in Survival), the game takes your position, scales it, keeps it inside the destination's world border and rounds it down to a block. Then it looks for nether portal blocks around that block. The area is a square, measured separately on X and on Z, and it covers the full height of the dimension.

Of all the portal blocks in that square, it picks the one closest to the target in a straight line, height included. When two are exactly as close, the lower one wins. Portals outside the world border are skipped. If nothing is found, the game builds a new portal: in a free spot within 16 blocks if it can find one, otherwise on a small obsidian platform it carves out. Java's Nether search used to be 128 blocks as well. It shrank to 16 in Java 1.16.2, which is why old advice often says 128 for both.

Two things follow from this. A link is never stored, so it can change the moment someone builds a portal closer to the target. And a link is not two-way by default: the portal you arrive at runs its own search on the way back, and that search can find a different portal.

Why does my Nether portal go to the wrong portal?

Because another portal was closer to the target than the one you meant. The common cases:

• Two Overworld portals share one Nether portal. You light a second Overworld portal, the game finds your first Nether portal inside the 16 block search area, and sends you there. Going back, that Nether portal leads to whichever Overworld portal is closer to it, so one of the two links is one-way.
• The partner was built in the wrong place. Usually a negative coordinate rounded the wrong way, or the X and Z swapped.
• The game built a portal for you. When you went through before the partner existed, the game made one nearby. That portal is still there and may be closer than the one you built later. Break it.
• A big height difference. A portal 3 blocks away sideways but 50 blocks lower loses to one 20 blocks away at the same height.

To fix a link, build the missing partner at the exact converted spot and break any portal the game made. Then add both to the checker: it shows the nearest portal and the runner up, so you can see how much room the link has.

How do you build two linked portals?

1. Build and light the first portal. Stand inside it and press F3. Note the "Block" line: that is the block your feet are in.
2. Convert it. Paste the line into the calculator. The other side shows the X, Y and Z for the partner.
3. Go through and walk to that spot. The game may drop you a little way off. In the Nether, dig or bridge to the converted coordinates.
4. Build the partner there, with the block you will stand in on the converted X and Z. Match the Y if you can.
5. Break the portal the game made when you first came through, unless it happens to be your partner spot.
6. Test both directions. Walk through and back. If the checker shows "Two-way" for both, the pair will hold.

On a server with many players, add everyone's portals near yours to the checker. A neighbor's portal 10 blocks from your Nether partner can take over your link.

How far apart do Nether portals need to be?

There is no fixed minimum. What matters is that each portal's partner is the closest portal to its target. In practice, keep Overworld portals at least about 24 blocks apart on X or Z. Their Nether spots are then 3 or more blocks apart, enough room for two separate frames. Closer than that, both Overworld portals land on the same Nether spot, and they will share one portal.

In the other direction, Nether portals can sit close together, as long as each one stands on its exact converted spot. Its Overworld target is then within a few blocks of its own partner, which beats any other portal more than a few blocks further out. In Bedrock, take extra care: a Nether portal there catches Overworld portals from up to 1,024 blocks away, so every Overworld portal needs its own partner on its exact spot.

How do you find your coordinates?

In Java Edition, press F3 (Fn + F3 on many laptops). The "XYZ" line is your exact position, the "Block" line is the block you are standing in, and the "Chunk" line shows the chunk. F3 + C copies your position as an /execute in minecraft:overworld run tp @s ... command, which you can paste into this calculator as is. A server can hide this with the reduced_debug_info game rule.

In Bedrock Edition, turn on "Show Coordinates" in the world settings, or run /gamerule showcoordinates true. The Position line in the top corner then shows X, Y and Z.

How do Nether hubs and highways work on a server?

A Nether hub is a central room, usually at Nether 0, 0, with tunnels running out along the axes. Each player builds a portal at their base, converts its coordinates, and digs a branch from the nearest tunnel to the partner spot. Because the Nether is 8 times smaller, a base 8,000 blocks from spawn is only 1,000 Nether blocks from the hub. The travel table above shows what that saves: a 5,000 block walk takes about 19 minutes in the Overworld and under 2.5 minutes through the Nether. Lay blue ice under a boat and it drops to seconds.

Highways on the roof (Java) avoid lava and mobs. Tunnels at about Y 120 are a good choice in Bedrock, where you cannot go above Y 127. Two server settings matter: allow-nether in server.properties has to be on, and the world border of each dimension caps where portals can lead (since Java 1.21.9 each dimension has its own). Pre-generating the Nether around the hub keeps the first trips smooth, see how to pre-generate your world, and fixing server lag helps when many players travel at once. If you want to set up a hub with friends, you can run a free Minecraft server on EternalZero.

The Nether also counts for an advancement: "Subspace Bubble" asks you to travel 7 km in the Overworld by using the Nether, which is 875 Nether blocks between two portals.

How does this calculator compare to other Nether calculators?

Most Nether calculators online convert one coordinate and stop there. Some cut off decimals instead of rounding down, which breaks negative coordinates. Many quote search radii from before Java 1.16.2 or mix up the editions. Few say anything about where the game will actually send you.

Everything runs in your browser. Nothing you enter is sent anywhere, and the page works offline once it has loaded. For the rest of your world, the seed map shows biomes and structures in the Nether too, which helps you plan where your hub tunnels will run.