How to Make a Nether Portal in Minecraft

Guide Java Bedrock

Quick answer: Build a vertical frame of obsidian at least 4 blocks wide and 5 blocks tall (10 obsidian minimum, corners optional) and light the inside with flint and steel. A full frame with corners uses 14 obsidian.

What you need

10-14 obsidian
Flint and steel (1 iron + 1 flint)
Diamond/netherite pickaxe OR water bucket + lava for casting

Step by step

Get obsidian: pour water over lava source blocks, then mine it with a diamond or netherite pickaxe. You need 10 (economy frame) or 14 (full frame).
Build the frame upright: two obsidian columns 3 blocks tall, joined by 2 obsidian at the top and 2 at the bottom. Interior space: 2x3.
Corners are optional - leave them empty to save 4 obsidian.
Light it: use flint and steel (1 iron ingot + 1 flint from gravel) on the inside of the frame. Fire from lava, a fire charge or a ghast fireball also works.
The interior fills with purple portal blocks. Stand inside for 4 seconds to teleport to the Nether.
No diamond pickaxe? Cast the portal in place: make a mold, place lava source blocks where the frame goes, then pour water on each to turn them into obsidian one by one.

Java vs Bedrock

Portal mechanics are the same in Java and Bedrock: minimum 4x5 frame, maximum 23x23. Linked portals match Overworld to Nether coordinates at an 8:1 ratio (X and Z divided by 8).

Versions: Unchanged since Alpha. Crying obsidian and ruined portals added in 1.16 - ruined portals can be repaired into working portals.

Frequently asked questions

How much obsidian do you need for a nether portal?

10 blocks minimum if you skip the four corners, or 14 for the complete 4x5 frame.

Why won't my nether portal light?

Check the frame is complete obsidian with a 2x3 empty interior, you are in the Overworld or Nether (portals do not form in the End), and you are lighting the inside face of the frame.

How do portals link between dimensions?

Each Overworld block equals 8 Nether blocks on X and Z. A portal at Overworld 800, 64, 800 links near Nether 100, ~64, 100. Y is not scaled.