Minecraft Sphere Generator
Enter a diameter from 1 to 256 blocks to generate a filled or hollow Minecraft sphere, sliced into build-order layers with a layer picker, each layer's block grid, and the total block count.
1 to 256.
Total blocks (whole sphere)
389
Layer 4 blocks
69
Y offset +0
Drag to see each horizontal slice from bottom to top.
| Layer (Y offset) | Blocks in layer | Running total |
|---|---|---|
| 0 (-4) | 13 | 13 |
| 1 (-3) | 37 | 50 |
| 2 (-2) | 49 | 99 |
| 3 (-1) | 61 | 160 |
| 4 (+0) | 69 | 229 |
| 5 (+1) | 61 | 290 |
| 6 (+2) | 49 | 339 |
| 7 (+3) | 37 | 376 |
| 8 (+4) | 13 | 389 |
How it's calculated
With radius r = diameter / 2, a block at (x, y, z) is inside the sphere when:
(x − center)² + (y − center)² + (z − center)² ≤ radius²
For a hollow sphere, a second test against a radius one block smaller removes everything but the outer shell. Grouping the result by Y gives the per-layer grids and counts shown above -- each one is itself a circle, generated by the same underlying test the Circle Generator uses in 2D.
Worked example: diameter 9
A filled diameter-9 sphere uses 389 blocks across its 9 layers; the widest layer (the equator, layer 4) alone needs 69 blocks. Hollowing out the same sphere to a one-block shell cuts that to 210 blocks -- a 46% reduction. Enter 9 into the generator above to reproduce these exact per-layer counts.
Frequently Asked Questions
How does the sphere generator turn a diameter into layers?
Every block in a diameter-N cube is tested against the true sphere equation (distance from center squared, compared to radius squared) in three dimensions at once -- it isn't built by stacking separately-computed circles. The result is then grouped by Y level into one layer per row of blocks, bottom to top, which is the order you'd actually place them in.
What's the difference between filled and hollow?
Filled places every block inside the sphere -- solid all the way through, good for a small decorative orb or a planet you'll never see the inside of. Hollow keeps only a one-block-thick shell, removing the interior -- the right choice for anything a player will stand inside, like a spherical room or a dome roof (see the Dome Generator for just the top half).
Why is the middle layer so much bigger than the top and bottom layers?
A sphere's cross-section is widest at its equator and narrows toward the poles -- the same reason a globe's circles of latitude shrink near the north and south poles. The layer table shows this directly: block count per layer rises to a peak at the middle layer, then falls off symmetrically.
Can I build just half of this sphere?
Yes -- that's exactly what the Dome Generator does: the same sphere geometry at the same diameter, cut at the equator and re-numbered from the base up.
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.