A Nether portal is a rectangular frame made of obsidian that opens a doorway to the Nether dimension

The portal itself is the frame only — you build it by placing obsidian blocks in a rectangle shape, then ignite the inside with flint and steel or a fire block. The frame must be at least 4 blocks wide and 5 blocks tall on the inside (so 6 blocks wide and 7 blocks tall if you count the frame itself). Once lit, the inside fills with purple swirling texture, and you can walk through it to enter the Nether.

The obsidian blocks are the only material that matters for the frame. You cannot use other blocks, and the frame cannot have gaps. The corners can be filled or empty — only the four sides need to be solid obsidian.

Key Takeaways

  • Obsidian is found deep underground near lava, and you need a diamond or netherite pickaxe to mine it — stone or iron pickaxes will not work.
  • The minimum portal size is 4 blocks wide and 5 blocks tall on the inside, which requires 10 obsidian blocks total if you skip the corners.
  • You light the portal with flint and steel (made from iron ingots and flint) or by placing fire inside the frame.
  • The portal takes you to the Nether, a hostile dimension where different mobs spawn and different blocks appear, and you can build a return portal there to get home.

Finding and mining obsidian

Obsidian forms when lava meets water. You will find it most often near lava pools deep underground, usually below Y-level 0 (you can see your Y-level in the debug screen by pressing F3 on Java Edition). Dig down to around Y-level -50 to -60 and look for lava lakes, then pour water on the lava to turn it into obsidian.

You can also find obsidian in the End dimension (the third dimension, accessed through an End portal) or by mining it directly if you find it already formed. Either way, you need a diamond pickaxe or better. An iron pickaxe will break the block but drop nothing. A stone pickaxe or wooden pickaxe will not break it at all.

If you do not have a diamond pickaxe yet, you need to find diamonds first. Diamonds spawn between Y-level -64 and Y-level 16, with the highest concentration around Y-level -59. Mine down to that level and dig horizontally, checking every block you pass.

Building the frame in the right shape

The portal frame is a hollow rectangle. The minimum size is 4 blocks wide and 5 blocks tall measured on the inside. That means if you are standing in front of it, you see 4 blocks across and 5 blocks up, with empty space in the middle.

You can build it larger — 5 wide and 6 tall, or 10 wide and 20 tall — and it will still work. The corners of the frame do not have to be filled with obsidian; you can leave them empty and the portal will still set up. Only the four sides (top, bottom, left, right) need to be solid obsidian with no gaps.

Place the obsidian blocks in a rectangular outline. Make sure every block in the frame is obsidian and there are no empty spaces along the edges. If you leave a gap, the portal will not light.

Lighting the portal with flint and steel

Once your frame is built, you need to ignite it. The most common way is with flint and steel. Flint comes from mining gravel (you get it randomly when you break gravel blocks), and steel 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. A purple swirling texture will fill the frame, and the portal is now active. You can walk through it when ready.

If you do not have flint and steel, you can also light the portal by placing a fire block inside the frame. Use a flint and steel to light a block on fire, or place a campfire inside the frame. Any fire inside the frame will set up it.

What happens when you enter the Nether

When you walk through the portal, you appear in the Nether dimension. The Nether is a hostile place with different blocks, different mobs, and different rules. Mobs like ghasts, blazes, and wither skeletons spawn here. The ground is made of netherrack, and you will find lava much more often than in the Overworld.

You can build a return portal in the Nether to get back home. Build another obsidian frame and light it the same way. When you enter it, you will return to the Overworld near your original portal (the game tries to place you at the same coordinates, but adjusted for the different scale of the Nether).

Why portals sometimes do not light

If you build a frame and flint and steel does not light it, check these things: make sure every block in the frame is obsidian with no gaps, make sure the frame is at least 4 wide and 5 tall on the inside, and make sure you are clicking inside the empty space, not on the obsidian itself.

If the frame is the wrong size (smaller than 4 by 5), the game will not let you light it. If there is a gap in the obsidian, the portal will not form. If you are clicking on the obsidian block instead of the empty space inside, nothing will happen.

Frequently Asked Questions

Can I build a portal in the Nether to go back to the Overworld?

Yes. Build another obsidian frame in the Nether and light it the same way. When you walk through it, you return to the Overworld. The game places you near your original portal, though not always at the exact same spot.

What if I do not have flint and steel yet?

You can light the portal with fire instead. Place a campfire or use flint and steel to light a block on fire inside the frame. Any fire inside the empty space will set up the portal. You can also find flint by mining gravel and iron by mining iron ore.

Do the corners of the obsidian frame have to be filled?

No. The corners can be empty. Only the four sides (top, bottom, left, right) need to be solid obsidian. A 4-by-5 portal needs only 10 obsidian blocks if you skip the four corners.

Can I make a portal bigger than the minimum size?

Yes. You can build a portal 5 wide and 6 tall, 10 wide and 20 tall, or any size larger than 4 by 5. Larger portals work the same way and look more impressive, but they use more obsidian.

What do I need to bring into the Nether?

Bring weapons, armor, and food. The Nether is dangerous and mobs deal more damage than in the Overworld. Bring a pickaxe if you want to mine netherrack or other blocks. Bring a way to light your way, like torches or lanterns, because the Nether is dark.