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CraftShape

30 Block Circle Generator

At 30 blocks across you are building an arena rather than a room. The curve is smooth enough that small mistakes stand out, so it is worth marking the widest rows before placing anything else.

Controls

Dimensions

Dimensions

blocks

This page is preset to one size — change it freely to explore others.

blocks

Always exactly half the diameter. An odd diameter has a half-block radius but still uses one single centre block.

Walls

Walls

Fill mode
blocks
Appearance

Appearance

Block color

Mirror mode shows one quadrant only. Build it, then mirror it left/right and front/back for a perfectly symmetrical shape.

Circle Generator

30 x 30 · 100 blocks

Drag to pan, scroll or pinch to zoom, hover a cell for coordinates.

Build summary

Diameter
30
Radius
15.0
Total blocks
100
Rows used
30

Symmetry check: mirrors left to right and mirrors top to bottom.

Ring built between the outer edge and an inner edge 1 block inside it.

Row-by-row instructions

  1. Row 1:skip 11 spaces, place 8 blocks
  2. Row 2:skip 8 spaces, place 3 blocks, leave 8 spaces, place 3 blocks
  3. Row 3:skip 7 spaces, place 2 blocks, leave 12 spaces, place 2 blocks
  4. Row 4:skip 5 spaces, place 2 blocks, leave 16 spaces, place 2 blocks
  5. Row 5:skip 4 spaces, place 2 blocks, leave 18 spaces, place 2 blocks
  6. Row 6:skip 3 spaces, place 2 blocks, leave 20 spaces, place 2 blocks
  7. Row 7:skip 3 spaces, place 1 block, leave 22 spaces, place 1 block
  8. Row 8:skip 2 spaces, place 1 block, leave 24 spaces, place 1 block
  9. Row 9:skip 1 space, place 2 blocks, leave 24 spaces, place 2 blocks
  10. Row 10:skip 1 space, place 1 block, leave 26 spaces, place 1 block
  11. Row 11:skip 1 space, place 1 block, leave 26 spaces, place 1 block
  12. Row 12:place 1 block, leave 28 spaces, place 1 block
  13. Row 13:place 1 block, leave 28 spaces, place 1 block
  14. Row 14:place 1 block, leave 28 spaces, place 1 block
  15. Row 15:place 1 block, leave 28 spaces, place 1 block
  16. Row 16:place 1 block, leave 28 spaces, place 1 block
  17. Row 17:place 1 block, leave 28 spaces, place 1 block
  18. Row 18:place 1 block, leave 28 spaces, place 1 block
  19. Row 19:place 1 block, leave 28 spaces, place 1 block
  20. Row 20:skip 1 space, place 1 block, leave 26 spaces, place 1 block
  21. Row 21:skip 1 space, place 1 block, leave 26 spaces, place 1 block
  22. Row 22:skip 1 space, place 2 blocks, leave 24 spaces, place 2 blocks
  23. Row 23:skip 2 spaces, place 1 block, leave 24 spaces, place 1 block
  24. Row 24:skip 3 spaces, place 1 block, leave 22 spaces, place 1 block
  25. Row 25:skip 3 spaces, place 2 blocks, leave 20 spaces, place 2 blocks
  26. Row 26:skip 4 spaces, place 2 blocks, leave 18 spaces, place 2 blocks
  27. Row 27:skip 5 spaces, place 2 blocks, leave 16 spaces, place 2 blocks
  28. Row 28:skip 7 spaces, place 2 blocks, leave 12 spaces, place 2 blocks
  29. Row 29:skip 8 spaces, place 3 blocks, leave 8 spaces, place 3 blocks
  30. Row 30:skip 11 spaces, place 8 blocks

Block counts for a 30 block circle

  • Hollow outline (1 block wall): 100 blocks
  • Filled disc: 716 blocks
  • Widest row: 30 blocks
  • Center: a 2x2 center square

Building advice for this size

  • Lay out the 2x2 center, then run four straight guide lines 15 blocks long to the outer edge in each direction.
  • Work one quadrant at a time and mirror it. Mirror mode in the controls shows exactly one quadrant to copy.
  • A 30 wide circle needs about one and a half stacks of blocks for a 1 thick ring, or five to six stacks for a 3 thick wall.
  • Check the shape from the air every few rows — errors are much easier to see from above than from inside the ring.

Other circle sizes

Smaller: 25 block circle. Larger: 40 block circle. Or open the full circle generator for any diameter up to 256.

Frequently asked questions

How many blocks does a 30 block circle need?
A hollow 30 block circle uses 100 blocks. Filled in it uses 716 blocks, which is roughly eleven stacks.
Is 30 blocks too big to build by hand?
No, but plan it. Build the ring on flat ground, place a torch at each of the four widest points, and copy one quadrant four times to keep it symmetrical.
What should I build with a 30 block circle?
Arenas, castle keeps, round farms, harbour platforms and the base of a large dome or observatory.

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