Dome generator for Minecraft

How to use it

1. Enter the base width. Leave the height empty for a perfect half sphere.
2. Choose a hollow shell for a roof, or solid for a mound.
3. Pick whether the dome has an open base or a floor layer.
4. Step through the layers from the base to the top and build each one.

How the dome is calculated

A dome is the upper part of an ellipsoid. The tool takes the base width w and the height h in layers. The block in layer j (counted from the base, starting at 0) at column i and row k is placed when its centre satisfies x² + y² + z² ≤ 1, where x and z are measured from the middle of the base in units of half the width and y = (j + 0.5) / h. With the height left empty the tool uses half of the width, rounded up, which gives a half sphere.

Hollow shells are made the same way as for spheres. A block stays when a face neighbour is empty, or when any neighbour is empty for the thick version. The open base option treats the space below the first layer as inside the dome, so the bottom ring is not turned into a floor.

A worked example: a 31 block dome

Take a base width of 31. The half sphere has 16 layers. With a thin hollow shell and an open base the layers have 84 blocks for the first five levels, then 80, 80, 76, 72, 68 and so on up to a cap of 45 blocks. In total that is 1,233 blocks, or 19 stacks and 17 blocks. Add a floor and it becomes 1,898 blocks. The thick shell needs 2,125, which is about 33 stacks and 13 blocks.

If you flatten the same dome to 10 layers, the count drops to 925 blocks. If you make it taller, 24 layers, it rises to 1,677. The height changes the look much more than it changes the cost, so it is worth trying a few values before you commit.

Block counts for half spheres

Building tips

Start by marking the centre and the outline of the base. Build the bottom layer first, then move up one layer at a time. The faint outline of the layer below helps you see where the new ring has to sit. At the top the cap layers are small, so build them last and check that nothing is missing in the middle.

For a big dome a central pole is a great helper. Place it from the floor to the top of the dome, and mark each layer on it. Every layer then has a known centre. Remove the pole when the shell is done and the top is closed.

If the dome sits on walls, build the walls first with the circle generator. Use the same diameter and the same line style, so the base ring of the dome lands exactly on top of the wall. A thin wall under a thin dome and a thick wall under a thick dome keep the joint clean.

Dome ideas

• Observatory or planetarium. A hollow dome with a single slot of glass blocks running from the base to the top.
• Greenhouse. A hollow dome with every block except the base ring replaced by glass.
• Underwater base. A dome with a floor layer, built on the ocean floor.
• Hill or mountain top. A solid dome covered with grass and trees makes a believable hill, but check the cost first.
• Roof of a round tower. Use the cylinder generator for the tower and match the dome width to its diameter.

Common mistakes

• Building from the top down. Start from the base. The wide layers decide where everything else goes.
• Mixing up width and radius. The width is the full distance across the base.
• Picking a height that is too small. A very low dome has huge flat layers at the top. Try at least a third of the width.
• Forgetting the stack count. A solid dome is several times more expensive than a hollow one. Use the numbers above the picture before you start mining.

Related generators

A dome needs something to sit on. Plan a round base wall with the cylinder generator at the same diameter as the dome. A half sphere is half of a full ball, so the sphere generator shows the same layers. The stack calculator converts the block count into stacks.

Sources and notes

The stack size of 64 and the layer model follow the standard block rules of the game, see the Minecraft Wiki (checked 25 October 2026). The dome shapes are computed by the tool. BlockShapes is not affiliated with Mojang or Microsoft.