Minecraft Nether Portal Calculator — Coordinates & Frame Size

Convert Overworld and Nether coordinates with the 1:8 ratio, and check portal frame size and link search radius in Minecraft Java and Bedrock.

July 4, 2026

Overworld X

Overworld Z

Y (optional, passthrough)

Nether Coordinates

(100, 64, -150)

Y is not scaled — it carries over unchanged. When you arrive, the game searches a 16-block radius (32×32 area) around this point in the Nether for an existing portal to link to before building a new one.

Overworld → Nether: divide X and Z by 8 and round down (floor), not to the nearest integer. Nether → Overworld: multiply X and Z by 8. The Y coordinate (height) is never scaled by the 1:8 ratio in either direction.

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Reference Values

Last verified: Jul 4, 2026

Category	Range	What It Means	Status
Overworld → Nether ratio ★	1:8 (divide X, Z by 8)	Every 8 blocks traveled in the Overworld equals 1 block in the Nether — the core reason Nether travel is so much faster for long distances.	★ Best
Nether → Overworld ratio ★	8:1 (multiply X, Z by 8)	The inverse conversion — 1 Nether block equals 8 Overworld blocks.	★ Best
Y-axis scaling ★	None — 1:1, unchanged	Height/depth is never scaled by the 1:8 ratio. A portal at Y=64 in the Overworld links to a Nether portal search centered on Y=64, not a scaled value.	★ Best
Overworld portal search radius	128 blocks (256×256 area)	When arriving from the Nether, the game searches this radius around the scaled coordinate for an existing Overworld portal before building a new one.	Good
Nether portal search radius	16 blocks (32×32 area)	When arriving from the Overworld, the game searches this much smaller radius in the Nether. Fixed to correctly account for the 1:8 scale in Java Edition 1.16.2+ — earlier versions used a larger, inconsistent radius that caused stray duplicate portals.	Good
Minimum outer frame size	4 wide × 5 tall	The smallest obsidian frame that can legally form a portal, giving a 2×3 interior opening.	Okay
Minimum interior opening	2 wide × 3 tall	The smallest empty space inside the frame that the game will fill with a portal surface.	Okay
Maximum interior opening ★	21 wide × 21 tall	The largest empty space the game will still recognize and fill with a portal surface.	★ Best
Maximum outer frame size ★	23 wide × 23 tall	Outer frame size corresponding to the maximum 21×21 interior opening.	★ Best

Source: Minecraft Wiki, 'Nether Portal' (https://minecraft.wiki/w/Nether_Portal) — coordinate ratio, portal linking/search radius, and frame size mechanics for Java and Bedrock Edition.

Worked Examples

Overworld → Nether Coordinate Conversion

Overworld X: 800
Overworld Z: -1200
Overworld Y: 64

Nether (100, 64, -150)

Divide X and Z by 8: 800 ÷ 8 = 100, and -1200 ÷ 8 = -150. Y passes through unchanged at 64 — height is never scaled by the 1:8 ratio.

Nether → Overworld Coordinate Conversion

Nether X: 100
Nether Z: -50
Nether Y: 70

Overworld (800, 70, -400)

Multiply X and Z by 8: 100 × 8 = 800, and -50 × 8 = -400. Y stays at 70.

Non-Even Coordinate Rounding

Overworld X: 243
Overworld Z: 15
Overworld Y: 70

Nether (30, 70, 1)

243 ÷ 8 = 30.375 and 15 ÷ 8 = 1.875 — both round down (floor) to 30 and 1, not to the nearest integer. This matters near coordinate 0, where flooring a negative fraction rounds further away from zero than expected.

Portal Search Radius Prevents a Duplicate Portal

New Nether arrival point: (100, 70, -50)
Existing linked Nether portal: (108, 64, -45)

Links to the existing portal — 8 blocks away, inside the 16-block search radius

The game searches a 16-block radius (Java 1.16.2+) around the scaled arrival point in the Nether. Since the existing portal is only 8 blocks away, it links to that portal instead of generating a new one nearby.

Frame Size Check for a Custom-Shaped Portal

Interior opening: 4 wide × 4 tall

Valid — above the 2×3 minimum and well under the 21×21 maximum

Any interior opening from 2×3 up to 21×21 works as long as it's a fully enclosed rectangle of obsidian (corners can be left empty — the game fills them automatically).

How to Use This Calculator

1

Pick a mode

"Coordinate Converter" translates positions between dimensions; "Portal Frame & Linking" checks frame size and explains the search radius.
2

Choose a direction

In the converter, toggle Overworld → Nether or Nether → Overworld depending on which coordinates you already have.
3

Enter your X, Z, and (optionally) Y

X and Z get scaled by the 1:8 ratio; Y is shown unchanged since height is never scaled.
4

Read the converted coordinates and search radius

The result also shows the block radius the game will search in the destination dimension when linking to an existing portal.

What Each Value Means

Horizontal Coordinate Ratio (ratio): The fixed 1:8 relationship between horizontal distance in the Overworld and the Nether — every 8 blocks traveled in the Overworld corresponds to 1 block in the Nether, and vice versa.
Portal Search Radius (blocks): The block radius the game scans around a scaled arrival coordinate for an existing portal before deciding to build a new one — 128 blocks in the Overworld, 16 blocks in the Nether.
Interior Opening (blocks (width × height)): The empty rectangular space inside an obsidian frame that the game fills with the portal surface once the frame is complete, ranging from 2×3 minimum to 21×21 maximum.

Frequently Asked Questions

How do I convert Overworld coordinates to Nether coordinates?

Divide your Overworld X and Z coordinates by 8 and round down (floor), not to the nearest whole number. Y (height) is never divided — it carries straight over unchanged. For example, Overworld (800, 64, -1200) becomes Nether (100, 64, -150). This calculator does the division and flooring for you, including the tricky negative-number cases.

Why didn't my new portal link to my old one — it just built a new portal instead?

Minecraft only searches a limited radius for an existing portal to link to: 128 blocks in the Overworld, but only 16 blocks in the Nether (as of Java Edition 1.16.2 and all current Bedrock versions). If your new portal's scaled coordinate lands outside that radius from your original portal, the game assumes there isn't one nearby and builds a fresh portal instead of connecting the two. This is the single most common reason players end up with unwanted duplicate portals.

Is Y (height) affected by the 1:8 ratio?

No. The 1:8 ratio only applies to the horizontal X and Z coordinates. Y passes through completely unscaled in both directions — a portal built at Y=120 in the Overworld searches for a matching portal at Y=120 in the Nether, not some divided or multiplied value. This trips up a lot of players who assume the ratio applies to all three axes.

What's the smallest and largest portal I can build?

The smallest legal portal has a 2-block-wide by 3-block-tall interior opening, needing a 4×5 outer obsidian frame. The largest has a 21×21 interior opening, needing a 23×23 outer frame. Anything outside that range — too small or too large — won't ignite as a portal. Corner blocks of the frame are optional; the game fills them in automatically once the rest of the rectangle is complete.

Does the coordinate ratio work differently on Bedrock Edition than Java Edition?

No — the core 1:8 horizontal ratio, the minimum/maximum frame sizes, and the general concept of a portal search radius are functionally identical between Java and Bedrock. The main practical differences are in what triggers automatic portal generation and some historical quirks in older versions' search radius (Java fixed its Nether-side search radius to correctly match the 1:8 scale in version 1.16.2). This calculator uses the current, corrected mechanics that apply to modern versions of both editions.