Minecraft Dome Generator
Enter a diameter from 1 to 256 blocks to generate a filled or hollow Minecraft dome (half sphere), sliced into build-order layers with a layer picker, each layer's block grid, and the total block count.
1 to 256 -- the diameter of the full sphere this dome is cut from.
Total blocks (whole dome)
229
Layer 0 blocks
69
Y offset +0 from the base
0 is the base ring, the top layer is the apex.
| Layer (Y offset) | Blocks in layer | Running total |
|---|---|---|
| 0 (+0) | 69 | 69 |
| 1 (+1) | 61 | 130 |
| 2 (+2) | 49 | 179 |
| 3 (+3) | 37 | 216 |
| 4 (+4) | 13 | 229 |
How it's calculated
This tool generates the full sphere for the diameter you enter -- the same three-dimensional distance test the Sphere Generator uses -- then keeps only the layers at or above the vertical center, re-numbered from 0 at the base to the apex at the top.
Worked example: diameter 9
A filled diameter-9 dome uses 229 blocks across its 5 layers -- exactly half, plus the shared equator layer, of the 389-block full sphere it's cut from. The base layer alone (layer 0, the widest ring) needs 69 blocks. Hollowed to a one-block shell, the same dome drops to 121 blocks. Enter 9 into the generator above to reproduce these exact per-layer counts.
Frequently Asked Questions
Is a dome a different shape from a sphere, or the same math?
Same math -- a dome is the upper half (from the equator up) of a full sphere at the same diameter, run through the identical distance-from-center test the Sphere Generator uses. It isn't a separately-designed curve, which is why a dome and a sphere at the same diameter always line up perfectly if you build a dome on top of a sphere's equator.
Should I use filled or hollow for a roof?
Hollow, almost always -- a filled dome as a roof wastes an enormous number of blocks on an interior nobody will ever see, and a hollow one-block shell looks identical from both inside and outside. Filled is really only useful for a small solid dome accent, like a knob or a decorative cap.
What diameter dome fits a round tower of a given width?
Match the dome's diameter to the tower's outer diameter (the same number you'd put into the Circle Generator for the tower's footprint) so the base ring of the dome sits flush on the tower wall -- check the base layer's grid above against your tower's own top layer before placing blocks.
Why does the base layer look like a full circle instead of a ring?
At the equator (layer 0 here), the sphere's cross-section is at its widest and, for a filled dome, completely solid -- the ring shape only shows up in hollow mode, where the shell test removes everything except the outer surface.
Circle In Blocks is a set of fan-made building tools, not affiliated with Mojang or Microsoft; Minecraft is a trademark of Mojang Studios. Grids are generated from the geometry described above, not pulled from the game itself -- see the Terms.