Minecraft Circle Generator

1. Set the diameter with the slider, between 3 and 50 blocks. The diameter is the full width of the circle measured in blocks: a diameter of 20 spans 20 blocks edge to edge. If you are building around a specific point (a fountain, a beacon), an odd diameter is handy because it leaves exactly one block at the center. 2. Choose the style: outline or filled. Outline draws only the outer ring — what you need to raise walls, towers or the rim of a dome — while filled marks every block inside, ideal for circular floors, platforms or ponds. 3. Read the grid. The result appears as a grid of characters in a monospace font: each █ is a block you place and each · is a gap you leave empty. Because the font is monospace, the columns line up perfectly and each row of the pattern matches a single row of your build. 4. Copy and build. Hit "Copy result" to grab the pattern, keep it on a second screen or your phone, and replicate it row by row in game. The counter tells you how many blocks you need in total — handy for stocking your inventory before you start.

All the calculation runs on your device, so you can generate as many circles as you like with no waiting and no connection once the page has loaded.

The underlying problem is translating a continuous circle into a grid of squares — what is known as rasterization. The tool starts from a grid whose side equals the diameter, with a radius r = diameter / 2 centered on it.

The test for each cell. To decide whether a cell belongs to the circle, it measures the distance from that cell's center to the circle's center. If the distance is less than or equal to the radius, the cell is part of the disk. In practice no square root is computed: the sum of the squared horizontal and vertical distances is compared against r², which is faster and exact. Sampling each cell's center (not its corner) is what gives the result its perfect symmetry.

Filled vs outline. With the filled style, every cell that passes the test is marked: the whole disk. With the outline style, only the edge of that disk is marked — cells that belong to the circle but have at least one neighbor (up, down, left or right) outside it. Defining the outline as the edge of the fill guarantees a single-layer ring, continuous and with no holes through which water or light would "leak" in your build.

This approach is a variant of the classic midpoint circle algorithm, described by Bresenham for drawing circles on pixel screens. That is why the circles you see are the same ones any graphics engine would draw: the block "staircase" is not a mistake, it is the mathematically correct way to approximate a curve with squares.

These are the cases where a circle pattern saves you hours of trial and error:

Building a dome is the showiest trick: generate several outlines of decreasing diameter (for example 15, 13, 11, 9…) and stack them on top of each other, each ring a little further in. Seen from outside, the steps blend into a half sphere.

For a tower, a single outline is enough: repeat the same row at every height and you get a perfect cylinder. If you want windows, leave symmetrical gaps by counting blocks from the center of each side.

For floors, use filled and start with the central row, which is the widest; that keeps you oriented and the rest falls into place. The block counter tells you how many units to buy or farm before you climb the scaffold.

• Confusing diameter with radius. The slider asks for the diameter, that is, the full width from edge to edge. If you wanted a circle with a 10-block radius, you need to set 20 as the diameter. This is the most common slip and the one that leaves the build at half size.
• Expecting a "perfect" circle at small diameters. Below 7-8 blocks, a circle has so few pixels that it looks more like an octagon, or even a square with bitten corners. That is not a flaw in the tool: it is the reality of rasterizing a curve on a tiny grid. For recognizable shapes, use diameters of 9 and up.
• Using an even diameter when you need an exact center. Even diameters have no single center block but a 2×2 square in the middle. If you are going to place a beacon, a pillar or a fountain right at the center, pick an odd diameter and you get an unambiguous central cell.
• Miscounting rows when building vertically. The pattern reads top to bottom, but in game you usually build facing forward. Mentally rotate the template 90°, or better, place it next to your screen in the same orientation you are building in, so you do not flip the drawing.
• Trying to fill an outline by hand. If you need a solid interior, do not fill the ring block by block: regenerate the same diameter with the filled style. The pattern already includes every interior cell and you avoid gaps left by mistake.

This generator solves that in seconds. Pick the diameter you need — anywhere from 3 to 50 blocks — and choose whether you want just the outline (great for towers, wells and domes) or a filled circle (perfect for round floors and platforms). The tool works out the exact grid with the midpoint algorithm, the same one graphics engines use to trace circles, and shows it as a pattern of blocks (█) and gaps (·) you can read row by row as you build. Everything happens inside your browser: nothing is uploaded to any server, no sign-up is needed and it is free. Copy the template, keep it next to you and replicate each row in your world — the result is a clean, symmetrical circle on the first try.