Minecraft Arch Generator

How to use the arch generator

1. Pick an arch type and set the span (width) and rise (height). A round arch is half as high as it is wide unless you turn on Elliptical.
2. Choose Blocks or Stairs and slabs and, for stairs, a material.
3. Set thickness and depth under the settings button (up to 8 thick and 16 deep).
4. Build row by row from row 1, the ground. Tap a block to see its row and column.
5. Print it, save a PNG or get a Minecraft file to paste it in one go.

Which arch type?

• Round: a half circle, for doorways, castle gates and aqueducts. A 15-wide round arch is 8 high and takes 21 blocks.
• Segmental: a slice of a larger circle, lower than a half circle, for bridges, shop fronts and fireplaces. At half the span or higher it becomes round.
• Pointed (gothic): two curves that meet in a point. A rise of about 0.87 times the span gives the classic shape (21 wide, 18 high); taller makes a narrow lancet.
• Catenary: a hanging chain turned upside down, for tunnels, mine entrances and modern halls.
• Parabolic: close to the catenary but a little slimmer toward the top, for gateways and big hangars.

Blocks vs stairs and slabs

Blocks mode gives the stepped look of most Minecraft arches. Stairs and slabs mode fills the steps with half blocks so both edges of the curve read as smooth lines. It needs more pieces: the 15-wide round arch goes from 21 blocks to 54 pieces when it is 2 thick (32 full blocks, 14 stairs and 8 slabs). Stairs are drawn as triangles and slabs as half blocks, with a count for each. Seven materials are available, from oak planks to deepslate bricks.

Doorways and bridges

The opening under an arch is the span minus the thickness on each side. For a 3-wide doorway with a 1-block frame, make a 5-wide round arch: 7 blocks. For a bridge, use a low segmental arch at least 2 blocks thick and set the depth to the width of the road. A 31-wide, 8-high bridge arch, 2 thick and 3 deep, takes 180 blocks (60 per slice).

Gothic windows

Gothic windows are pointed arches that are taller than they are wide. Try a 7-wide, 9-high lancet (17 blocks for the frame) and fill the inside with glass or stained glass panes. Put three side by side with the middle one taller.

Matching an arch to a circle wall or a dome

A round arch on an odd span is exactly the top half of the circle of the same width in the circle generator, so a 15-wide arch follows the same blocks as the top of a 15-wide circle (40 blocks in all as a thin circle). It is also the middle slice of the half-sphere dome on the same base in the dome generator. Use that to cut a matching entrance into a dome or line up a vaulted ceiling with a round tower.

Minecraft files and commands

Open Minecraft files and commands under the tool. Download a .schem file for WorldEdit on Java (//schem load with the file name including .schem, then //paste -a), a .mcstructure file for Bedrock (/structure load from a behavior pack), or copy /fill commands or a .mcfunction file. In Stairs and slabs mode the commands and the .mcfunction use Java block names and states, so on Bedrock use the .mcstructure file.

What was tested: five arches, two of them in stairs and slabs, were loaded on Paper 1.21.11 with WorldEdit 7.4.2 and Bedrock Dedicated Server 1.26.63.1 and checked block by block, including which way every stair faces. Every block matched. The Bedrock structure block Import screen and Bedrock /fill commands were not tested. If a file does not work for you, use Report a problem in the panel.

Arch block counts

Blocks for one slice, 1 block thick, from the same engine as the generator. Multiply by the depth for a deeper arch. The Stairs column is the round arch in stairs and slabs, 2 thick, in pieces. Select a number to open it.