The ratio is the whole trick
The Nether is a compressed coordinate space: moving 1 block there moves you 8 on the Overworld map. A 3,000-block journey becomes 375 Nether blocks — a few minutes of tunnel instead of a full inventory of boats. Divide Overworld X and Z by 8 to find where your Nether-side portal should sit.
Stop portals linking to the wrong place
The game links a portal to the closest existing portal within 128 blocks (Nether coordinates). Building a second portal carelessly is how players spawn inside someone else’s tunnel. The fix: place Nether-side portals at your calculated coordinates, not wherever you happen to exit, and keep portals at least 128 blocks apart in the Nether when you want them independent.
Build standards
The frame needs 10 obsidian minimum (corners optional) lit with flint and steel. For safety build a stone enclosure and a clear landing pad on both sides — Ghast fireballs and cliff drops are the classic Nether portal surprises. Carrying a flint and steel through the portal protects you from Ghasts re-lighting costs.
