Plan pixel circles block by block
Round shapes are the hardest thing to build in a block world. This pixel circle generator draws circles, filled discs and ellipses on a square grid and tells you exactly how many blocks go in every row, so you can build towers, domes, arenas and pixel art without guessing.
Choose the size, an outline thickness or a filled shape, and how outline blocks should join. Circles use the classic midpoint (Bresenham) circle algorithm; ellipses and the alternative “cell centre” option fill every block whose centre lies inside the shape. Download the result as PNG, SVG or a CSV of row counts, or print it to keep next to you while you build.
How to use the pixel circle generator
- Enter the width in blocks. Untick “Circle” to set a different height for an ellipse or oval.
- Pick Outline or Filled. For an outline, set the thickness in blocks.
- Choose the joins: Thin lets blocks touch only at corners on the diagonals; Solid wall adds a block at every corner so nothing can slip through.
- Read the blocks in each row from the table — rows count from the top, columns from the left — or hover over the drawing to see a block’s row and column.
- Download a PNG, SVG or CSV, or press Print for a paper copy.
Pixel Circle Generator features
Midpoint circle algorithm
The classic Bresenham-style circle, with correct odd and even diameters.
Thickness and joins
Outlines of any thickness, with thin (diagonal) or solid-wall joins.
Ellipses and filled discs
Any width and height up to 200 blocks, outlined or filled.
Blocks per row
Counts, runs and start columns for every row, plus the total and stacks of 64.
PNG, SVG, CSV and print
Export the grid with centre lines, or the row table as a spreadsheet.
How the circles are drawn
The midpoint circle algorithm walks around one eighth of the circle, one column at a time, and at each step keeps the same row or moves one row in — whichever keeps the cell closer to the true circle (it tests the midpoint between the two candidates). The other seven eighths are mirror images. A 5-block circle comes out as rows of 3, 2, 2, 2 and 3 blocks: 12 in all.
Odd diameters have a single centre block; even diameters are centred between two blocks, so the centre lines on the drawing fall on a grid line. Both are drawn exactly, which matters when the circle has to line up with a doorway or a pillar.
The cell centre method marks every block whose centre lies inside the circle or ellipse. It works for any width and height, so ellipses always use it. Results are very close to the midpoint circle and sometimes identical.
Thickness, joins and filled shapes
A filled disc takes every block between the outline’s ends in each row. An outline of thickness t is made by peeling t layers off the filled shape, so the wall stays the same thickness all the way round.
Thin joins treat blocks as touching only at their sides when peeling, giving the familiar staircase where diagonal blocks meet at a corner. Solid wall also counts corner neighbours, adding a block at each step so the wall has no diagonal gaps — useful when it must be airtight or keep creatures out. It uses a few more blocks.
Tips for building
- Build a quarter first. Every shape is symmetric left–right and top–bottom, so the other quarters are mirror copies.
- For a dome or sphere, generate one circle per layer with shrinking diameters and build them in order.
- Odd diameters are easier to centre on a single block; even diameters suit a 2-block-wide doorway or corridor.
- Use the CSV to tick off rows as you go, or print the diagram. For freehand pixel art, try the pixel art editor.
Pixel Circle Generator FAQ
How do I make a pixel circle?
Enter the diameter in blocks and read the blocks per row from the table, starting at the top. The diagram shows exactly which blocks to place.
Can I make a pixel circle with thickness?
Yes. Choose Outline and set the thickness in blocks. Pick solid-wall joins if the wall must have no diagonal gaps.
What is the midpoint circle algorithm?
A classic way to draw circles on a grid (also called Bresenham’s circle algorithm). It steps around one eighth of the circle and picks the closer of two cells each time.
Should I use an odd or even diameter?
Odd diameters have one centre block; even ones are centred on a line between blocks. Pick the one that lines up with the rest of your build.
Can it draw ovals and ellipses?
Yes — untick Circle and set a different height. Ellipses use the cell-centre method.
How big can the circle be?
Up to 200 × 200 blocks. Grid lines are drawn up to 120 blocks so large shapes stay readable.