A Nether portal is a rectangular frame made of obsidian that you light with flint and steel to travel to the Nether dimension

The Nether is a dangerous alternate dimension in Minecraft filled with lava, hostile mobs, and valuable resources. To reach it, you build a frame from obsidian blocks arranged in a specific pattern, then ignite it. The portal itself is the purple swirling space inside the frame — stepping into it transports you to the Nether. On your home network, this works the same way whether you're playing single-player or on a multiplayer server.

Building a portal requires two materials you'll need to gather first: obsidian and flint and steel. Obsidian forms when water flows over lava source blocks, and flint and steel is crafted from iron ingots and flint. Once you have both, the actual frame takes about five minutes to build and light.

Key Takeaways

  • Obsidian is the only block that won't break when you light the portal, and you create it by pouring water over stationary lava.
  • The frame must be at least 4 blocks wide and 5 blocks tall on the inside, with obsidian forming the corners and edges but not the interior.
  • Flint and steel is crafted from one iron ingot and one flint, and you use it to ignite the purple portal blocks that form inside the frame.
  • Once lit, the portal stays active permanently unless you break the obsidian frame or the blocks inside it.

Gathering obsidian by creating it from lava and water

Obsidian doesn't spawn naturally as a block you can mine — you have to make it. Find a lava pool or lava lake (common in the Overworld at any depth, but more frequent below Y-level 0). You need a water bucket to pour water over the lava source block. When water touches a lava source block, it hardens into obsidian when ready.

The key word is source block. If you pour water over flowing lava, it creates cobblestone instead, which won't work for a portal. Lava that spreads downward from a higher block is flowing lava. A lava source block is one where the lava surface looks flat and level — it's the original block the lava came from. Dig down into the lava pool until you find the flat surface, then pour your water bucket over it from the side or above.

You'll need at least 10 obsidian blocks for a minimal portal frame (4 wide by 5 tall), but gather 14 to 16 to account for mistakes or to build a larger, more stable frame. Each time you pour water over a lava source, you get one obsidian block. Mine it with a diamond or netherite pickaxe — wooden, stone, and iron pickaxes won't break obsidian. A diamond pickaxe takes about 10 seconds per block.

Crafting flint and steel to ignite the portal

Flint and steel is a tool that creates fire when you use it. You craft it from one iron ingot and one flint. Iron ingots come from smelting iron ore in a furnace. Flint drops from gravel blocks when you mine them — dig through a gravel patch and collect the flint that falls out.

Open your crafting table and place one iron ingot in any slot and one flint in an adjacent slot (the exact positions don't matter). The flint and steel appears in the output slot. You only need one flint and steel to light the portal, and it doesn't break after one use — you can light multiple portals with the same tool. However, flint and steel does have durability and will eventually wear out after many uses, so keep a spare if you plan to light portals frequently.

Building the obsidian frame in the correct shape

The portal frame must be rectangular and at least 4 blocks wide and 5 blocks tall on the inside (the empty space where the purple portal will appear). The obsidian forms the border — the corners and all four edges. The interior must be completely empty for the portal to light.

The simplest frame is 4 wide by 5 tall inside, which uses 10 obsidian blocks arranged like this: place obsidian in a rectangle, with the bottom row having 4 blocks, the top row having 4 blocks, and the left and right sides having 5 blocks each (the corners are shared). If you're building a larger frame, such as 5 wide by 6 tall, use more obsidian but keep the same rule — obsidian only on the edges, nothing in the middle.

Find a flat area where you want the portal. Place your first obsidian block on the ground. Build a row of 4 blocks to the right. At the end of that row, place a block above it, then continue upward 4 more times (5 blocks tall total). Go back to the starting block and build upward 5 times. Connect the top with 4 blocks going right. You now have a hollow rectangle. The interior space is where the portal will appear.

Lighting the portal with flint and steel

Stand in front of the empty interior of the frame and hold your flint and steel in your hand. Right-click (or use your secondary action button) on any of the obsidian blocks that form the frame. A small spark appears, and the interior of the frame fills with purple swirling blocks — that's the active portal. The portal is now ready to use.

If nothing happens when you click, check that the interior is completely empty (no blocks or items inside the frame) and that the frame is the correct size. A frame that's too small won't light. If the frame is correct and still won't light, try clicking a different obsidian block in the frame.

Once lit, the portal stays active permanently. You can walk through it, and it will transport you to the Nether. On a multiplayer server, the portal works the same way — any player can use it, and it remains lit until someone breaks the obsidian frame.

What happens when you step through the portal

Stepping into the purple portal blocks transports you to the Nether. You'll appear in a corresponding location in the Nether dimension, usually near a Nether portal that's already there (the game creates one automatically if it doesn't exist). The Nether is much more dangerous than the Overworld — you'll encounter blazes, ghasts, hoglins, and other hostile mobs when ready. Bring armor, weapons, and food before your first trip.

To return to the Overworld, find or build another Nether portal in the Nether and light it the same way. Stepping through takes you back to the Overworld near your original portal. On a multiplayer server, portals work the same way, but be aware that other players can use your portals too.

Troubleshooting portals that won't light or disappear

If your portal won't light, the most common cause is an incomplete frame. Check that all four corners have obsidian and that the entire border is filled with no gaps. The interior must be completely empty — even a single block or torch inside will prevent the portal from lighting. If you're certain the frame is correct, try clicking a different obsidian block, as the game sometimes requires you to click a specific edge.

If a portal lights but then disappears, someone broke one of the obsidian blocks. On a multiplayer server, check with other players. On single-player, verify that no blocks fell into the frame or that you didn't accidentally break part of it. Rebuild the missing obsidian and light it again.

If you're on a multiplayer server and the portal is in a shared area, consider building it in a protected zone or asking an admin to protect it. Some servers have grief-prevention plugins that let you claim land so other players can't break your portal.

Frequently Asked Questions

Can I make a portal smaller than 4 by 5?

No. The minimum interior size is 4 blocks wide by 5 blocks tall. Smaller frames won't light no matter how much flint and steel you use. You can make it larger — 5 by 6, 6 by 7, or bigger — but not smaller.

What if I don't have a diamond pickaxe to mine obsidian?

You can't mine obsidian with anything except a diamond or netherite pickaxe. If you don't have one yet, gather diamonds first. Diamonds spawn below Y-level 16 and are found in ore blocks. Once you have three diamonds, craft a pickaxe at a crafting table. Then use it to mine your obsidian.

Do I need to build a portal frame in the Nether too?

The game creates a Nether portal automatically when you step through an Overworld portal, so you don't have to build one. However, if you want to create a portal in a specific location in the Nether, you can build and light one the same way you do in the Overworld.

Can I move a portal after I light it?

No. Once a portal is lit, it stays in that location. If you want a portal elsewhere, build a new frame and light it. You can break the obsidian blocks of an old portal to reclaim the material and use it for a new one.

What's the difference between a portal in single-player and on a server?

They work identically. On a server, other players can use your portal, and you can use theirs. If someone breaks your portal's obsidian frame, it goes dark and you'll need to rebuild it.