# Where do I build my Nether portal?

Converts Minecraft coordinates between the Overworld and the Nether: X and Z divide by 8 going to the Nether and multiply by 8 coming back, and Y stays the same.

- Page: https://www.acalculator.org/game/nether-portal-calculator
- JSON spec: https://www.acalculator.org/game/nether-portal-calculator.json
- Version: 75e55aecdd5a

## Default answer

Example with the default inputs (Convert Overworld to Nether, X coordinate 1,000, Y coordinate 64, Z coordinate -300): Converting Overworld to Nether from X 1,000, Z -300: build the portal at X 125, Y 64, Z -38.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| from | Convert | Whether you start from Overworld coordinates or from Nether coordinates. |
| x | X coordinate | The X coordinate (east–west for X, north–south for Z) in the dimension you start from. |
| y | Y coordinate | The height. It is the same in both dimensions. |
| z | Z coordinate | The Z coordinate (east–west for X, north–south for Z) in the dimension you start from. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| coordinates | Build the portal at | The block coordinates X, Y, Z in the other dimension: X and Z rounded down. |
| blockX | Block X | The X coordinate in the other dimension, rounded down to a whole block. |
| blockZ | Block Z | The Z coordinate in the other dimension, rounded down to a whole block. |
| exactX | Exact X | X ÷ 8 going to the Nether, X × 8 going to the Overworld, before rounding. |
| exactZ | Exact Z | Z ÷ 8 going to the Nether, Z × 8 going to the Overworld, before rounding. |
| note | Note | Shown when the target is outside the world border or in the Nether’s bedrock roof or floor. |
| blockY | Y | The height, unchanged. |

## Method

Overworld to Nether: X ÷ 8 and Z ÷ 8; Nether to Overworld: X × 8 and Z × 8; Y is unchanged; block coordinates round down.

## Assumptions

- Horizontal distances in the Nether are 1/8 of the Overworld’s (Java and Bedrock editions).
- Block coordinates are rounded down (floor), as the game does, so −37.5 becomes −38.
- The game links a portal to the nearest existing portal within a search range, so two portals close together may link to the same one.

## Worked examples

1. from = overworld, x = 1,000, y = 64, z = -300 gives exactX = 125, exactZ = -37.5, blockX = 125, blockZ = -38, coordinates = X 125, Y 64, Z -38. Source: hand calculation in content.mdx: 1000 ÷ 8 = 125; −300 ÷ 8 = −37.5, rounded down to −38.
2. from = nether, x = 100, y = 70, z = -20 gives exactX = 800, exactZ = -160, coordinates = X 800, Y 70, Z -160. Source: hand calculation in content.mdx: 100 × 8 = 800; −20 × 8 = −160.
3. from = overworld, x = 15, z = 7 gives exactX = 1.875, blockX = 1, blockZ = 0, coordinates = X 1, Z 0. Source: hand calculation in content.mdx: 15 ÷ 8 = 1.875 → 1; 7 ÷ 8 = 0.875 → 0.

## FAQ

### How do Nether coordinates work?

One block walked in the Nether equals 8 blocks in the Overworld, east–west (X) and north–south (Z). Height (Y) is not scaled. So Overworld X 1000, Z −300 is Nether X 125, Z −37.5.

### How do I link two Nether portals?

Build the Overworld portal first. Divide its X and Z by 8 and build the Nether portal at those coordinates (rounded down), at a height the Nether allows. When you go through, the game looks for a portal near the matching point and links to the closest one.

### Why is the result rounded down?

The game turns a position into a block by rounding down (floor). −37.5 rounds down to −38, not −37, and 1.875 rounds down to 1.

### Why did my portal link to the wrong portal?

The game searches for an existing portal around the matching point: up to 128 blocks from it in the Overworld, and 16 blocks in the Nether in Java Edition. If two portals are closer together than that, both can link to the same one. Build each portal at its exact matching coordinates.

### Does the Y coordinate change?

No. Heights are the same in both dimensions. The Nether’s usable height is lower, so a portal high up in the Overworld may need a portal built lower in the Nether.

## Sources

- Minecraft Wiki, World border (29,999,984 blocks from the origin by default): https://minecraft.wiki/w/World_border
- Minecraft Wiki, The Nether (bedrock floor Y 0 to 4, roof Y 123 to 127, Java Edition): https://minecraft.wiki/w/The_Nether
- Minecraft Wiki, Nether portal (coordinate scale, rounding, search range): https://minecraft.wiki/w/Nether_portal