You need 10 obsidian for the smallest Nether portal in Minecraft, because the four corners of the frame are optional; fill in the corners too and the same portal takes 14. That frame is 4 blocks wide and 5 blocks tall, which leaves a 2 by 3 opening that you light with flint and steel. Below we cover the frame rules, the largest portal the game allows, every way to light one, and how to make all 10 obsidian with water and lava if you do not own a diamond pickaxe yet.
This applies to the current version of Minecraft on both editions: Java Edition 26.3 and Bedrock Edition 26.50, the Wilderness Bound drop released on September 15, 2026, on PC, PlayStation, Xbox, Nintendo Switch and mobile. Neither that drop nor the first 26.4 snapshot changes how portals are built.
The Obsidian Count at a Glance
| Portal | Frame (outside) | Opening | Obsidian without corners | Obsidian with corners |
|---|---|---|---|---|
| Smallest | 4 wide x 5 tall | 2 x 3 | 10 | 14 |
| Largest | 23 x 23 | 21 x 21 | 84 | 88 |
Any rectangle between those two sizes works, and it does not have to be square. For any size, the obsidian you need without corners is twice the opening’s width plus twice its height, so a 3 by 4 opening takes 14 blocks. Bigger portals do nothing extra; they just look grander.
Why the Corners Do Not Matter
The game only checks the obsidian that touches the opening: two blocks along the bottom, two along the top and three up each side on the smallest frame. The four corner spots can be empty or filled with any block you like, such as cobblestone or dirt. Per the community wiki, portals the game builds on its own, such as the one that appears on the far side when you first travel, always include the corners, which is why most screenshots show a full rectangle.
A few other rules decide whether a frame works:
- It must stand upright. It can face either direction, but a frame laid flat on the ground never lights.
- Only regular obsidian counts. Crying obsidian, the purple-speckled block found in ruined portals, cannot be part of a working frame.
- The opening must be clear. Remove any blocks or leftover water from inside the frame before lighting it.
- Not in the End. Nether portals only activate in the Overworld and the Nether.
How to Light a Nether Portal
Flint and steel is the standard tool. Craft it from one iron ingot and one flint; flint drops some of the time when you break gravel. Select it on your hotbar and use it on the inside of the frame, usually on top of one of the bottom obsidian blocks. The purple portal fills the whole opening at once.
| Action | PC (Java and Bedrock) | Xbox | PlayStation | Nintendo Switch |
|---|---|---|---|---|
| Place a block or use flint and steel | Right-click | LT | L2 | ZL |
| Mine a block | Hold left-click | Hold RT | Hold R2 | Hold ZR |
| Cycle the hotbar | Mouse wheel or 1 to 9 | LB / RB | L1 / R1 | L / R |
Anything that puts fire inside the frame works too. Per the community wiki, that includes a fire charge (crafted from blaze powder, gunpowder and coal or charcoal), a ghast or blaze fireball, a lightning strike, or fire spreading from a flammable block beside the portal, which is how some players light one with lava alone. Ruined portal chests also often hold flint and steel or fire charges, so a player with no iron to spare can still get through.
How to Get Obsidian Without a Diamond Pickaxe
Obsidian only drops when you mine it with a diamond or netherite pickaxe, and even then each block takes around nine seconds. Anything weaker breaks it slowly and drops nothing. The workaround is to never mine it at all: you cast the obsidian directly into the frame shape. This works because flowing water that touches a lava source block turns that lava into obsidian on the spot.
You need two buckets (three iron ingots each), one of water and one of lava, a stack of dirt or cobblestone for scaffolding, and flint and steel. Then:
- Work beside a lava pool, so each refill is a few steps away, and keep clear of trees and wooden builds, which lava sets on fire.
- Build a pocket for each obsidian block out of temporary dirt or cobblestone, so the lava you pour has nowhere to run. Start with the two bottom blocks, often simply a two-block trench dug into the ground.
- Pour lava into the pocket, then pour water on a block beside or above it so the water flows over the lava. The lava hardens into obsidian instantly.
- Scoop the water back up with your empty bucket, refill the lava, and repeat up each side and across the top.
- Break the scaffolding and clear the opening. The corner spots can stay as dirt or cobblestone.
- Light it with flint and steel.
The one thing that goes wrong: only a lava source block, the kind you pour from a bucket or find sitting still in a pool, becomes obsidian. Water hitting a lava stream makes cobblestone instead, and lava that pours down onto water makes stone. Crafting a few extra buckets lets you carry several loads of lava per trip.
Ruined Portals: The Shortcut
Ruined portals are broken frames scattered across the Overworld, usually surrounded by netherrack and magma blocks. Many are only a few blocks short, and you can finish one with cast obsidian instead of building from scratch. Check it first: any crying obsidian sitting in a side, top or bottom position has to be replaced, and that takes a diamond pickaxe, so without one look for a ruin whose crying obsidian (if any) sits only in the corners. The chest next to the ruin is worth opening either way, since per the community wiki it can hold obsidian, flint and steel, fire charges and gold gear.
Before You Step Through
Wear at least one piece of gold armor so piglins stay neutral, and carry a spare flint and steel, because a ghast’s fireball can knock out your portal and strand you. Distances also shrink in the Nether: one block traveled there equals eight in the Overworld, which makes portals handy for fast travel later. On Java, the map mods in our 50 best Minecraft mods, such as Xaero’s Minimap with its waypoints, make finding your way back to a portal far easier. Minecraft also sits on our best co-op PS5 games list if you would rather make the trip in split-screen, and our Minecraft LIVE September 2026 coverage explains where Mojang is taking the game next.
Frequently Asked Questions
How many obsidian blocks do you need for a Nether portal? 10 for the smallest working portal, since the corners are optional. With all four corners filled in, it takes 14.
Can you make a Nether portal without a diamond pickaxe? Yes. Pour lava into each spot of the frame and let water flow over it so it turns into obsidian in place. You never have to mine a block.
What is the biggest Nether portal you can build? A 23 by 23 frame with a 21 by 21 opening. That takes 84 obsidian without corners, or 88 with them.
Can you use crying obsidian in a Nether portal? No. Only regular obsidian works in the frame, although crying obsidian is fine in a corner, since corners are not checked.
Why won’t my Nether portal light? Usually a non-obsidian block sits in a side, top or bottom position, something is blocking the opening, the frame is lying flat or bigger than 23 by 23, or you are trying to light it in the End.