How to use it
- Choose Cylinder or Cone and enter the diameter and height.
- Pick a hollow wall for a tower, or solid for a pillar.
- Decide whether the top and the bottom are open or closed.
- Build the first layer from the plan, then repeat it upward. For a cone, step through the layers because each one shrinks.
How the shapes are calculated
A cylinder is one circle layer repeated. The tool decides each block with the same test as the circle generator: a block is placed when its centre lies inside the circle of the chosen diameter. The wall of a hollow cylinder keeps the blocks that have an empty face neighbour. If the ends are open, the space above and below the build counts as part of the inside, so the floor and the roof are not turned into a solid cap. If they are closed, the first and last layers are filled discs.
A cone shrinks the radius with every layer. In layer j of a cone with height h the radius is the base radius times (1 - j / h). The last layer is a single block or a very small cluster, which gives the point.
A worked example: a watchtower
A watchtower with a diameter of 13 and a height of 20 has a ring of 36 blocks on every layer. For 20 layers that is 720 blocks, exactly 11 stacks and 16 blocks. If you close the bottom with a floor disc and the top with a roof disc, the first and last rings turn into filled discs of 137 blocks, which brings the total to 922. A solid pillar of the same size would need 2,740 blocks, about three times as many as the closed hollow tower.
Thinner towers cost surprisingly little. A tower 9 blocks wide and 30 blocks tall also needs 720 blocks with open ends, because its ring is only 24 blocks. A tower 21 blocks wide and 40 tall needs 2,240 blocks as a thin wall and 3,200 with the thick wall.
A worked example: a cone roof
A cone with a diameter of 21 and a height of 15 has a thin hollow shell with 714 blocks when its bottom is closed. The layers are 349, 52, 48, 44, 40, 36, 32, 28, 24, 20, 16, 12, 8, 4 and 1 blocks. If you leave the bottom open, the 349 block floor turns into a ring and the total drops to 421 blocks. A solid cone of the same size has 1,879 blocks.
For a witch hat or a steeple, build the cone on top of a cylinder of the same diameter. Make the cylinder end with an open top so the two parts join without a double layer.
Block counts for common towers
| Diameter | Height | Hollow, open ends | Hollow, closed | Solid |
|---|---|---|---|---|
| 9 | 30 | 720 | 810 | 2,070 |
| 13 | 20 | 720 | 922 | 2,740 |
| 21 | 40 | 2,240 | 2,826 | 13,960 |
Design tips
- Use floors every 4 or 5 blocks. A player needs two blocks of headroom plus the floor, so rooms that are 4 blocks tall inside feel normal and 5 blocks feel airy.
- Add a rim at the top. Replace every second block of the top ring with a different block, or step the top layer outward by one block. This makes the tower look finished at no cost.
- Break the wall. A tall plain wall looks flat. Add vertical stripes of another block, windows every few layers, or buttresses at the four compass points.
- Plan the stairs first. A tower with a spiral staircase needs a pillar in the middle. Use an odd diameter and the spiral staircase generator on this site.
Common mistakes
- Counting only one layer. The number above the picture is the whole build, the count under the layer slider is for a single level.
- Forgetting the world height. In Java Edition 1.18 and later the Overworld is 384 layers high, from Y -64 to Y 319. The Nether and the End are 256 layers.
- Mixing styles. If the wall is thin and the floor is thick, the corners will not line up. Keep one style for the whole build.
- Building the cone upside down. The widest layer is at the bottom. Layer 1 in the slider is the base.
Related generators
A cylinder is a stack of circles, so the circle generator gives you the row guide for a single layer. Cap the tower with a dome, or plan the inside with the spiral staircase generator. When the totals are ready, the stack calculator turns them into chests.
Sources and notes
World height figures are from the Minecraft Wiki page on height limits (checked on 25 October 2026). Shapes and counts are computed by the tool. BlockShapes is not affiliated with Mojang or Microsoft.
Frequently asked questions
How do I make a round tower in Minecraft?
Draw one circle layer with the diameter you want, then build the same layer on top of itself until the tower reaches its height. The tool shows the plan for one layer and multiplies it for the full height.
How many blocks does a cylinder need?
A hollow tower with a diameter of 13 and a height of 20 needs 720 blocks when both ends are open, because each layer has 36 blocks. With a floor and a roof it needs 922. A solid pillar of the same size needs 2,740.
What diameter is best for a tower?
For a tower you can walk around in, 9 to 15 blocks gives room for stairs and a few rooms. Odd diameters have a centre block, which suits a central pillar or a spiral staircase. Even diameters have a 2 by 2 core.
How do I build a cone or a spire?
Switch the shape to Cone. The base is the full diameter and each layer above it is a little narrower until the top ends in a single block. Check the layer plans one by one and build from the bottom.
What is the difference between hollow and hollow, thick?
A hollow wall is one block thick. The thick option adds the corner blocks, so the wall is two blocks thick in the diagonal parts and has no diagonal gaps. It looks sturdier and costs more.
Can I make a cylinder lying on its side?
Build it upright using the plan, then turn the plan in your head: the layers become slices along the long axis. For a short horizontal pipe it is easier to draw the circle on a vertical wall with the circle generator and extend it sideways.