How to use the sphere generator
- Enter the diameter in blocks. The sphere will be this wide and this tall.
- Pick a shell thickness, or tick Solid for a filled ball (useful for planets and terraforming).
- Move through the layers with the slider. Each layer is one horizontal slice, starting from the bottom. Build layer 1, go up one block, build layer 2, and so on.
- Watch the pale "layer below" blocks to line each ring up with the one under it.
Tips for building spheres in survival
- Build the middle ring first. The widest layer (the middle one) fixes the size. Then build upwards and downwards from it.
- Use scaffolding. The bottom half of a sphere overhangs, so place scaffolding or dirt pillars under it and remove them afterwards.
- Count the materials first. A hollow 21-block sphere needs 1,082 blocks. Check the total above and convert it with the stack calculator.
- Only need the top half? The dome generator shows just the upper layers, starting at the widest ring.
Sphere build ideas
Planets and moons in a space map, snow globes, giant bubbles for underwater bases, glass biodomes, mob farms, lanterns and decorative orbs on castle towers.
How the sphere is calculated
A block at position (x, y, z) belongs to the sphere if its centre satisfies x² + y² + z² ≤ r². For a hollow shell, a block is kept only if one of its six face neighbours is outside the sphere (checked up to your chosen thickness). This produces an airtight shell with no holes between layers — important if you are building underwater or want to keep mobs out.
Frequently asked questions
How do you build a sphere in Minecraft?
Build it one horizontal layer at a time. Enter the diameter, start at layer 1 (the bottom) and use the slider to move up one layer as you build up one block. The pale blocks show the layer below so you can line each ring up.
How many blocks are in a Minecraft sphere?
It depends on the diameter and whether it is hollow. A hollow 21-block sphere with a 1-block shell needs 1,082 blocks. The generator gives the exact total and a count for every layer.
Is the hollow sphere watertight?
Yes. A block is only removed from the shell if all six of its neighbours are inside the sphere, so there are no gaps between layers.
What is the biggest sphere I can build?
The generator goes up to 128 blocks across. In the Overworld (Java 1.18 and later) you have 384 blocks of build height, so even the largest sphere fits.