How to Make a Voxel Circle: Free Generator, Radius Charts & Block Guide

A voxel circle is a circle approximated on a discrete 3D grid — each point on the curve is a cube-shaped cell (a voxel) sitting at a whole-number coordinate. Here’s the catch: because those coordinates are integers, you can never draw a mathematically perfect circle out of voxels. What you can do is find the grid cells that land closest to the ideal circle — and that’s the entire job of a voxel circle generator.

This guide walks through how voxel circles actually work, gives you copy-ready block charts for the common radii, and shows how to build hollow circles, filled discs, and rings. Doesn’t matter whether you’re building in Minecraft, modeling voxel art, or just trying to lay out a round room in a game — the grid maths are the same.

Why you can’t draw a perfect circle on a grid

A real circle is a continuous curve — every point sits exactly the same distance from the center. A voxel grid doesn’t have that luxury. It only has cells at integer positions: (0,0), (1,0), (2,0), and so on. There’s nothing at (1.7, 3.4), so that smooth curve has to be snapped to the nearest cells it can actually use.

What you get is a staircase. From a distance it reads as a circle; up close it’s straight runs and little steps. Pixel artists have wrestled with the exact same thing in 2D for decades — a voxel circle is really just the 3D version of a pixel circle.

The go-to fix is the midpoint circle algorithm, which you’ll also see called Bresenham’s circle. It only bothers computing one-eighth of the circle — at each step it decides whether to keep going straight or drop inward — then mirrors that little arc across all eight octants to finish the shape. Fast, deterministic, and about as clean as a grid circle gets.

1 Ideal circle A continuous curve at radius r from the center

2 Test each cell Find grid cells whose distance is closest to r

3 Snap to grid Midpoint algorithm picks the nearest integer cells

4 Mirror x8 Compute one octant, reflect it into the other seven

You’ll never run this by hand — the generator spits it out instantly — but it’s worth knowing it’s an approximation. That’s why tiny circles look chunky, and why two different tools can hand you slightly different circles at the very same radius. Neither is wrong; they just rounded a few border cells differently.

The three shapes: hollow, filled, and ring

“Circle” on a grid actually means three different things depending on what you’re after, and the generator covers all three.

Hollow circle

1. 1. Just the outline — one cell thick
2. 2. Best for: round walls, towers, pipes, rims
3. 3. The outer boundary only, interior left empty
4. 4. Lowest block count of the three

vs

Filled disc

1. 1. Every cell inside the radius is solid
2. 2. Best for: floors, platforms, table tops, sphere layers
3. 3. Use as a single slice when stacking into a sphere or cylinder
4. 4. Highest block count — grows with the square of the radius

Then there’s the ring — the band between two radii, basically a filled disc with a smaller disc punched out of the middle. Set an outer radius and an inner one and you can dial in any thickness you want. It’s the shape you reach for with arena seating, moats, road loops, clock faces, decorative borders, that kind of thing.

Hollow circle, filled disc, and ring at radius 16 — side by side Image to be added

Voxel circle radius chart

Before you place a single block, it pays to know two numbers: the diameter (how wide it’ll be) and the block count (how much material you’ll burn). A hollow circle of radius r is 2r + 1 blocks across, and its block count climbs more or less linearly with the radius. A filled disc is a different beast — its count grows with the square of the radius, so it balloons fast.

Radius	Diameter (blocks across)	Hollow circle (≈ blocks)	Filled disc (≈ blocks)	Good for
3	7	16	29	Small details, pillars, dots
4	9	20	49	Round windows, small towers
5	11	28	81	Fountains, small rooms
8	17	44	197	Towers, domes, gazebos
10	21	56	317	Round rooms, ponds
12	25	68	437	Large towers, silos
16	33	92	797	Arenas, big domes
20	41	112	1,257	Lakes, stadiums
24	49	136	1,793	Massive structures

Treat those counts as ballpark — the exact total shifts a little depending on how the algorithm rounds each octant. The generator shows a live block count for whatever radius and shape you’ve dialed in, so you can budget materials before you ever break ground.

How to make a circle in Minecraft (block by block)

Minecraft runs on the same integer grid every voxel tool uses, which means a voxel circle chart is a Minecraft circle chart — no conversion needed. Here’s the workflow:

1. Pick your radius and generate the hollow shape.
2. Find the four cardinal points — the lone blocks at the top, bottom, left, and right of the chart. They sit right on the center axes (the generator marks the origin for you), which makes them easy to line up against a build you’ve already started.
3. Lay blocks along the curve between each pair of cardinal points, reading the chart cell by cell. Good news: you only ever have to read one quarter of it. The other three quarters are just mirror images, so once you’ve done one you’ve effectively done them all.
4. Stack straight up for a cylinder or tower — same hollow circle, repeated on every layer.

From circle to sphere, dome, and cylinder

Here’s the nice part: once you can make a filled disc, the round 3D shapes basically fall out for free. They’re all just discs stacked up with a changing radius.

• Cylinder — easiest of the bunch. Stack the same circle on every layer (hollow for a pipe, filled for a solid column). Radius never changes.
• Sphere — stack filled discs that shrink as you climb toward the top and bottom. At height h above the center of a sphere of radius R, the disc you want has radius round(√(R² − h²)). Generate one per layer and stack them.
• Dome — same disc stack as the sphere, you just stop at the equator and keep the top half.

1 Pick sphere radius R e.g. R = 10 → 21 layers tall

2 Layer radius At each height h, radius = round(√(R² − h²))

3 Generate disc Make a filled disc at that layer radius

4 Stack Place each disc at its height to build the volume

And if doing the layer math by hand sounds tedious — it kind of is — you can skip it. Describe the shape to the Voxel AI editor, let it generate a full sphere, dome, or rounded structure, and then go in and refine it cell by cell.

Exporting your circle

Three ways to get a circle out of the browser:

• Download PNG — a clean, high-res chart (voxel-circle-r{radius}.png) to keep open as a build reference.
• Copy pattern — the ASCII grid as plain text, paste it wherever.
• Open in editor — pushes the circle into the Voxel AI editor as a real .vox model (encoded in MagicaVoxel’s format). From there you can extrude it into a tower, stack it into a sphere, or just use it as the floor plan for something bigger.

And since .vox is a standard format, that same circle opens just fine in MagicaVoxel, Goxel, or anything else that reads .vox. (Still picking an editor? Our comparison of voxel software lays out the options.)

Tips for better voxel circles

• Bigger is smoother. Circle looks too blocky? Nine times out of ten the fix is a larger radius, not a different tool.
• Share a center when nesting. Concentric circles — a ring road, a target, an amphitheater — only line up cleanly if they sit on the same origin. The generator keeps the origin pinned to the center, so they will.
• Reach for rings on thick walls. Don’t fuss with two separate hollow circles to fake thickness. Set a ring with the inner and outer radius you want and you get the exact band in one shot.
• Let the block count plan your materials. That live number is a real estimate — genuinely handy before a big survival build, or when you’re trying not to blow your voxel budget on a model.

Voxel circle FAQ

How do I make a circle out of voxels or blocks? You approximate it. Integer coordinates rule out a perfect circle, so the midpoint (Bresenham) algorithm grabs the cells closest to the ideal boundary instead. The generator handles that for any radius and gives you a chart to copy.

What is a voxel circle? A circle drawn on a discrete 3D grid, where each point is a cube-shaped cell at a whole-number coordinate — basically the 3D version of a pixel-art circle. New to all this? Start with what a voxel is.

How do I make a circle in Minecraft? Generate the hollow shape at your radius, then place a block on every filled cell of the chart — start at the four cardinal points and follow the curve around.

What radius should I use? 3–5 for small details, 8–16 for rooms, towers, and domes, 20+ for arenas and lakes. Things read as round from about radius 8 up.

How do I make a sphere or dome? Stack filled discs, sizing each one with round(√(R² − h²)) at its height. A dome is just the top half of that stack.

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That’s the whole thing. Open the Voxel Circle Generator → — free, no account needed. Want full 3D models from a text prompt instead of building by hand? Try the Voxel AI editor (the free tier comes with 50 tokens), or get your bearings first with our guide to voxel art.