seedlookoutJAVA AND BEDROCK · OVERWORLD AND NETHER
Nether portal calculator
Convert Overworld coordinates to Nether coordinates, or back, to find where a portal leads and where to build its partner.
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How the conversion works
One block of horizontal travel in the Nether equals 8 blocks in the Overworld. To get the Nether position, the game divides Overworld X and Z by 8 and rounds down. To go back, it multiplies Nether X and Z by 8. Y is not scaled in either direction.
Rounding down means rounding toward the smaller number, so negative coordinates move away from zero. Overworld X −1 becomes Nether X −1, and X −9 becomes −2. Dropping the decimal instead would give 0 and −1, one block off.
How the game picks a portal
When you step through a portal, the game converts your position and looks for an existing portal near that point. It checks a square around the point at every height, then sends you to the closest portal by straight-line distance, counting the difference in Y. A portal at a very different height can lose to one that is farther away horizontally.
| Arriving in | Java Edition | Bedrock Edition |
|---|---|---|
| Overworld | 128 blocks (256×256) | 128 blocks (256×256) |
| Nether | 16 blocks (32×32) | 128 blocks (256×256) |
If no portal is in range, the game builds a new one at the closest suitable spot within 16 blocks horizontally of the converted point, at any height. If it finds no room, it forces a portal at the converted X and Z, with Y kept between 70 and 10 below the world height (Y 118 in the Nether), and adds a small obsidian platform. In Java Edition most entities can create a portal this way; in Bedrock Edition only players can.
Height, the Nether roof and the world border
The Nether has a bedrock floor from Y 0 to 4 and a bedrock ceiling from Y 123 to 127. The ceiling’s top layer is Y 127, so the roof above it starts at Y 128. Because Y is copied unchanged, an Overworld portal at Y 150 converts to a point above the ceiling. Build its Nether partner below the ceiling, at a height as close to the Overworld portal as you can.
In Java Edition the Nether’s build limit is 256, so players who reach the roof can build on it. In Bedrock Edition the Nether’s build limit is 128.
Converted X and Z are kept inside the default world border, from −29,999,984 to 29,999,983. This only matters for Nether X or Z beyond ±3,749,998, which would otherwise convert past the edge of the Overworld.
How to link two portals
- Stand in your Overworld portal and read your position. In Java Edition, press F3 to open the debug screen. In Bedrock Edition, turn on Show Coordinates in the world options. Note X, Y and Z.
- Enter those numbers in the calculator with Overworld → Nether selected.
- Go through the portal. If you arrive at a portal the game generated away from the calculated Nether X and Z, travel to that point.
- Build and light a Nether portal there, below the ceiling at Y 123 and as close to the Overworld portal’s Y as the terrain allows.
- Go back through the new Nether portal. It leads to your original Overworld portal if no other Overworld portal is closer to its converted point. If a trip still lands somewhere else, another portal in range is closer: break it or move one of the pair.
To connect a Nether portal to a new Overworld base, do the same with Nether → Overworld selected.
Nether portal calculator FAQ
How do I convert Overworld coordinates to Nether coordinates?
Divide X and Z by 8 and round down, and keep Y. Overworld X 1,000, Z −500 becomes Nether X 125, Z −63, because −62.5 rounds down to −63.
Why did I come out of the wrong portal?
The game sends you to the closest portal within its search area, measured in three dimensions. Another portal in range, a large height difference or the side of a wide portal you stepped into can change which one is closest. Each Nether block you can stand in converts to a different 8-block stretch of the Overworld.
Is it different in Bedrock Edition?
The 1:8 conversion is the same. Bedrock Edition searches 128 blocks around the converted point when you arrive in the Nether, where Java Edition searches only 16. Both search 128 blocks when you arrive in the Overworld.
Does the Y coordinate matter?
Y is not divided or multiplied, but it counts when the game measures which portal is closest. If two Overworld portals share the same X and Z at different heights, a Nether portal at the matching position leads to the one closer to its own Y.
Do I need my seed?
No. The calculator only uses coordinates, so it works in any world. To plan a route to a fortress or bastion from your seed, use the Nether fortress finder, the bastion remnant finder or the seed map.
Sources
Game mechanics on this page are summarised from these Minecraft Wiki revisions (CC BY-NC-SA 3.0): Nether Portal, The Nether, World border, Coordinates and Tutorial: Nether portals. We have not separately checked these mechanics in game.