The basic structure: obsidian blocks in a frame shape
A Nether portal is a rectangular frame made of obsidian blocks that you light on fire to open a doorway to the Nether dimension. The frame itself is 4 blocks wide and 5 blocks tall on the inside — meaning the outer edge is 6 blocks wide and 7 blocks tall. You do not need to fill in the middle; the empty space is what becomes the portal when you light it.
The quickest way to gather obsidian is to find lava and pour water on it. When lava cools under flowing water, it turns into obsidian blocks. You will need a diamond or netherite pickaxe to mine obsidian; a stone pickaxe or weaker will not break it. If you do not have a diamond pickaxe yet, you can also find obsidian in the End dimension or in the Nether itself, though that requires already having a portal.
You can build the frame in any orientation — standing upright, lying flat on the ground, or even sideways on a wall. The portal will work the same way regardless of how you position it.
Key Takeaways
- A Nether portal frame is 4 blocks wide and 5 blocks tall on the inside, made entirely of obsidian with no blocks filling the center space.
- You light the portal by clicking any block inside the frame with flint and steel, which ignites purple fire that opens the doorway.
- Obsidian is gathered by pouring water on lava and requires a diamond or netherite pickaxe to mine.
- The frame can be built in any direction — standing, lying flat, or on a wall — and the portal will function the same way.
- Once lit, a portal stays active until you break the obsidian frame or the fire goes out from water or rain.
Gathering obsidian without a diamond pickaxe
If you are still in early game and do not have diamonds yet, you have two options: create obsidian from lava and water, or find it in naturally generated structures. The lava-and-water method is the most reliable. Find a lava pool or lava lake, then pour water on top of it or let water flow down onto it. Where the water touches the lava, obsidian forms. You can then mine it with a diamond pickaxe once you obtain one.
Alternatively, obsidian generates naturally in certain structures: the End portal frame in the End dimension, strongholds, and some village structures. If you have already reached the End, you can mine the obsidian blocks from the portal frame itself — though this requires defeating the Ender Dragon first or finding a way around it.
Once you have at least 10 obsidian blocks (the frame needs 10, though having extras is useful), you can begin building your portal.
Building the frame step by step
Place your first obsidian block on the ground or wherever you want the portal to be. From there, build a vertical line of 5 blocks upward. At the top of that line, build a horizontal line of 4 blocks to the right. Then build a vertical line of 5 blocks downward. Finally, connect the bottom with a horizontal line of 4 blocks back to your starting point. You should now have a rectangular frame with an empty 4-by-5 space in the middle.
The corners can be obsidian or empty — the portal only requires the four long sides to be complete. Many players leave the corners empty to save obsidian, though it does not affect how the portal works.
If you are building on uneven ground, make sure the frame is level. A tilted or incomplete frame will not light. Double-check that the inside space is exactly 4 blocks wide and 5 blocks tall before moving to the next step.
Lighting the portal with flint and steel
Once your frame is built, you need flint and steel to light it. Flint drops from gravel blocks when you mine them — you need to mine several gravel blocks to collect flint. Steel (also called iron ingots) comes from smelting iron ore in a furnace. Combine one flint and one iron ingot in a crafting table to make flint and steel.
Hold the flint and steel in your hand and right-click (or use your secondary action button) on any block inside the empty frame space. A purple fire will ignite, and the entire frame will fill with a purple swirling portal. The portal is now active and you can walk through it to enter the Nether.
If the fire goes out — from rain, water, or being in the Nether for too long — you can light it again with flint and steel. You do not need to rebuild the frame.
What happens when you step through
Walking into an active Nether portal takes you to the Nether dimension, a dangerous realm filled with lava, hostile mobs, and valuable resources. When you enter, you will spawn near a corresponding portal on the Nether side. The Nether portal on that side will already be lit and ready to use.
If you break the obsidian frame on either side, the portal stops working on both sides. You can rebuild it or light a new one. The Nether is also a place where water does not flow normally and fire spreads quickly, so be careful where you build or place your portal.
To return to the Overworld (your main world), straightforward walk back through the Nether portal. You will arrive back at your original portal location.
Common mistakes that prevent portals from working
The most frequent problem is an incomplete frame. If even one block is missing from the four sides, the portal will not light. Count carefully: 5 blocks on each vertical side, 4 blocks on each horizontal side, with the corners being part of the vertical count.
Another common issue is using the wrong material. Only obsidian works for the frame itself. Blocks that look similar, like dark prismarine or blackstone, will not create a portal. If you are unsure whether a block is obsidian, check your inventory or use a crafting recipe to confirm.
If you are in Creative mode, you can also use a Nether portal block directly from the creative inventory, which skips the frame-building step entirely. In Survival mode, you must build the frame and light it with flint and steel.
Frequently Asked Questions
Can I build a Nether portal in the Nether itself?
Yes. You can build a second portal in the Nether to create a new exit point, or to link to a different location in the Overworld. Each portal you build will connect to a corresponding location on the other side, based on the game's coordinate system.
What if my portal frame is tilted or on uneven ground?
The frame must be level and complete to light. If your ground is uneven, fill in the low spots with dirt or other blocks first, then build the obsidian frame on top. The portal itself does not care what is underneath it, only that the frame is straight and intact.
Do I need to build the frame in a specific direction?
No. The frame can face any direction and can be built standing upright, lying flat, or even sideways on a wall. The portal will work the same way regardless of orientation. Choose whichever direction is most convenient for your base or travel route.
Can other players destroy my Nether portal?
On a multiplayer server, yes — anyone with access to your area can break the obsidian blocks. If you want to protect your portal, you can surround it with blocks that are harder to break, or use server permissions to restrict access to that area.
What if I light the portal but nothing happens?
Check that the frame is complete and level. If blocks are missing or the frame is tilted, the portal will not set up. Also make sure you are using actual flint and steel, not a different item. If the frame is correct and you are using the right tool, try lighting it again — sometimes the fire needs a moment to spread.