What you need before you start building

A Minecraft portal is a doorway that takes you to another dimension — either the Nether or the End. To build one, you need specific materials that you craft or find, and you need to place them in the exact shape the game recognizes. The Nether portal is the one most players build first, because you can gather the materials in your starting world.

For a Nether portal, you need obsidian blocks. Obsidian forms when water flows over lava source blocks, or you can mine it directly with a diamond or netherite pickaxe if you find it underground. You need at least 10 obsidian blocks to build the smallest working portal, though the standard size is 14 blocks (a rectangle that is 4 blocks wide and 5 blocks tall on the inside).

For an End portal, the process is different — you do not build it at all. Instead, you find it in a stronghold deep underground, and you activate it by placing Eyes of Ender into the frame blocks that are already there. This guide covers building a Nether portal, which you control completely.

Key Takeaways

  • A Nether portal requires at least 10 obsidian blocks arranged in a rectangular frame, with the inside measuring at least 2 blocks wide by 3 blocks tall.
  • You can create obsidian by pouring water over lava source blocks, or mine it directly with a diamond or netherite pickaxe.
  • The frame must be solid obsidian on all four sides — the corners can be obsidian or empty, but the edges cannot have gaps.
  • Once the frame is complete, you light it on fire using flint and steel, a fire charge, or lava, and the purple portal appears instantly.
  • Portals work in both directions — stepping into a Nether portal from the overworld takes you to the Nether, and stepping into one there takes you back.

Gathering obsidian the fastest way

The quickest method is to find lava and water, then create obsidian on the spot. Lava pools are common underground, especially below Y-level 0 (you can see your Y-level in the debug screen by pressing F3 on Java Edition). Dig down until you find lava, then place water above it or beside it so the water flows over the lava source block. The lava will turn into obsidian instantly.

If you do not have a diamond pickaxe yet, this is the faster route than mining obsidian directly, because mining obsidian with a stone or iron pickaxe takes 50 seconds per block and you cannot pick it up — the block breaks and disappears. A diamond pickaxe mines it in about 9 seconds and lets you keep it.

Once you have your obsidian blocks, carry them to a flat area where you want to build the portal. You do not need to be in any specific biome — portals work anywhere in the overworld.

Building the frame in the correct shape

Place your obsidian blocks in a rectangle. The minimum size that works is 2 blocks wide and 3 blocks tall on the inside (meaning the frame itself is 4 blocks wide and 5 blocks tall including the obsidian). This uses 10 blocks total. The standard size most players use is 4 blocks wide and 5 blocks tall on the inside, which uses 14 blocks.

Start by placing the bottom row of obsidian blocks in a line. Then place a block on each end to form the sides, and continue building up. The corners can be empty or filled with obsidian — the game does not care. What matters is that all four edges have obsidian blocks with no gaps.

If you make a mistake, simply break the obsidian block with your pickaxe and place it again. Obsidian does not break when you mine it with a diamond or netherite pickaxe — you always pick it back up.

Lighting the portal to activate it

Once your frame is complete, you need to set it on fire. Use flint and steel (crafted from one flint and one iron ingot), a fire charge (crafted from blaze powder, coal, and gunpowder), or simply place lava next to the frame. Click or tap the inside of the frame with your fire source, and the purple swirling portal appears instantly.

The fire does not need to stay lit — the portal remains active even after the fire goes out. You can walk through it immediately. If the portal does not appear, check that your frame has no gaps in the edges and that the inside is completely empty (no blocks in the way).

What happens when you step through

Stepping into the portal takes you to the Nether, a dangerous dimension filled with lava, hostile mobs, and valuable resources. You will arrive in a random location in the Nether, usually on a platform of obsidian or netherite. The Nether is much hotter and more hostile than the overworld, so bring armor, weapons, and food.

To return, you can either build another portal in the Nether (using obsidian you find there or bring with you) or find the portal you came through — it still exists on the Nether side. Stepping back through takes you to the overworld, though you may not arrive at the exact spot you left. The game links portals based on coordinates, so a portal at X=100, Z=100 in the overworld connects to a portal at X=12.5, Z=12.5 in the Nether (the Nether is 8 times smaller).

Common mistakes that break your portal

The most common error is leaving gaps in the frame edges. Every block on all four sides must be obsidian — if you have a 1-block gap anywhere, the portal will not light. Check each edge carefully before you try to light it.

Another mistake is placing blocks inside the frame. The inside must be completely empty for the portal to work. If you have obsidian, dirt, or any other block inside the rectangle, break it out first.

Some players also try to light the portal with regular fire (from a flint and steel that is out of durability, or from a torch). Regular fire does not work — you need an active fire source. Flint and steel, fire charges, and lava all work reliably.

Building a second portal for faster travel

Once you have explored the Nether and gathered resources, you can build a second portal there to create a fast-travel route. Build a Nether portal in the Nether using obsidian you find or bring with you. When you light it and step through, you will arrive back in the overworld at a location linked to your Nether portal's coordinates.

This is useful for traveling long distances in the overworld. Because the Nether is 8 times smaller, traveling 800 blocks in the Nether gets you 6,400 blocks in the overworld. Build a portal in the Nether, use it to return to the overworld, and you have covered a huge distance in the overworld without walking it.

Mark the location of both portals with signs or torches so you can find them again. Portals can be hard to spot in the dark, and the Nether is very dark.

Frequently Asked Questions

Can I build a portal in the Nether that goes to the End?

No. Nether portals only go to the Nether, and End portals only go to the End. You cannot build an End portal — it exists only in strongholds underground. To reach the End, you must find a stronghold, locate the End portal frame, and place Eyes of Ender in the frame blocks.

What if I build a portal but it will not light?

Check that every edge block is obsidian with no gaps, and that the inside is completely empty. If both are true, try lighting it again with flint and steel or a fire charge. If it still does not work, break the frame down and rebuild it — you may have made a mistake in the shape.

Do I need to build a portal in a specific location?

No. You can build a Nether portal anywhere in the overworld, in any biome, at any height. The location does not matter for the portal to work. However, building it near your base makes it easier to find when you return from the Nether.

Can other players use my portal?

Yes, on multiplayer servers. Any player can step through a portal you build. If you want to prevent this, you can build a wall around the portal or place it in a locked room.

What if I fall into lava while building obsidian?

Wear armor and bring a water bucket. If you fall into lava, place the water bucket on the block below you to create a platform and stop the fall. You will take some damage, but you will survive if you have armor and health.