Minecraft Arches: Exact Patterns & Block Counts (3–21 Wide)

The usual advice for Minecraft arches is to go up one block and in one block until the two sides meet, which builds a triangle. A round arch is the top half of a hollow circle two blocks wider than the opening: over a 9-block doorway that is an 11-block circle, and its top 6 rows come to 15 blocks — three straight up each side, two diagonal steps, then a flat crown five blocks long.

That mix of straight, diagonal and flat is different at every width, and it does not grow the way you would guess. The 7-wide arch takes more blocks than the 9-wide one.

Table of contents

Opening width plus two

To size a round arch in Minecraft, add 2 to the width of the opening and generate a hollow circle of that diameter. A ring one block thick spends one block on each side of the opening, so the ring that frames a 9-block doorway is 11 across. A “9 block arch” usually means the opening, the part you walk through, and that is the number every table on this page starts from.

Set the diameter in the circle generator with Fill Mode on Hollow. MC Shapes is a free, browser-based set of Minecraft shape generators (circle, oval, sphere and dome) that outputs block-by-block blueprints with exact block counts; it does not export schematic files. MC Shapes does not have a Minecraft arch generator either. The circle generator draws the ring, and reading the arch off it is your job: you want every row from the top of the ring down to and including its widest row.

Including the widest row changes the count. The Materials panel reports Total Blocks for the whole ring, which is 28 for the 11-block circle, and halving that gives 14. The arch is 15. On an odd circle the widest row sits on the centre line and belongs to the arch, so an arch cut from an odd circle is always half the ring plus one block. On an even circle there is no centre row and the arch is exactly half: a 12-block circle is 32 blocks, and the 10-wide arch cut from it is 16.

Everything under the widest row is pillar, and you need less pillar than you might think. The arch rows already include some straight side, three rows of it at 9 wide, and a 9-wide arch has 5 blocks of clear height under its crown before any pillar is added.

Minecraft arch patterns from 3 to 21 wide

These are round arches, one block thick. Each row of the table reads from the crown down to the widest row of the ring, and each number is how many blocks that row holds. So 5-2-2-2-2-2 is a top row of five blocks followed by five rows with one block on each side.

A 5-wide arch is 9 blocks over 4 rows, and a 9-wide arch is 15 blocks over 6 rows. At 13 wide the arch is 21 blocks over 8 rows; at 21 wide it has grown to 37 blocks and stands 12 rows tall. Those counts are for a ring one block thick and one block deep, in the pattern this generator draws. A circle chart that rounds its corners differently will give a different number for the same width, which is how two guides can disagree about a 9-wide arch and both be right about their own drawing.

Counts per row do not tell you where in the row the blocks sit, so here are the odd sizes from 3 to 13 drawn out. # is a block and . is air.

3 wide  (circle 5, 3 rows, 7 blocks)
.###.
#...#
#...#

5 wide  (circle 7, 4 rows, 9 blocks)
..###..
.#...#.
#.....#
#.....#

7 wide  (circle 9, 5 rows, 17 blocks)
..#####..
.##...##.
##.....##
#.......#
#.......#

9 wide  (circle 11, 6 rows, 15 blocks)
...#####...
..#.....#..
.#.......#.
#.........#
#.........#
#.........#

11 wide  (circle 13, 7 rows, 21 blocks)
....#####....
..##.....##..
.##.......##.
.#.........#.
#...........#
#...........#
#...........#

13 wide  (circle 15, 8 rows, 21 blocks)
.....#####.....
...##.....##...
..#.........#..
.#...........#.
.#...........#.
#.............#
#.............#
#.............#

For any other width, read the positions off the blueprint. Click the blocks of the top half and each one changes colour, which leaves you a marked-up arch to build from and the rest of the ring to ignore.

The 7-wide arch costs more than the 9-wide one

A 7-wide arch is 17 blocks and a 9-wide arch is 15, because the two circles they are cut from are drawn differently. In the 9-block circle the diagonal steps sit edge to edge, so the ring is two blocks thick through its corners. The 11-block circle steps corner to corner and stays one block thick all the way round. You can see it in the grids above: the 7-wide arch has a doubled block at each shoulder and the 9-wide one does not.

The same thing happens further up the table. An 11-wide arch and a 13-wide arch are both 21 blocks. A 17-wide arch is 35 blocks, and the 19-wide arch after it drops to 29.

I ran every opening from 3 to 21 through the same algorithm the generator uses and printed each grid, mostly to check the table. The 9-, 13- and 19-block circles all came out with those edge-to-edge corners; the 11-, 15- and 21-block circles did not. I cannot give you a rule for which is which. The corners land wherever the radius happens to fall against the block edges at that one size, and nothing in the sequence of sizes predicts it.

Two things follow. You cannot budget an arch by scaling up from a smaller one, so take the count for your width from the table. And if you want the thinner look at 7 wide, you can leave out the inner block of each doubled step, four blocks in all, and land on 13. Whether that reads as elegant or as flimsy depends on the wall around it. I would leave the doubled corners in on anything built from stone brick, where some weight at the shoulders looks right.

Odd openings get a keystone, even ones fit a double door

An odd opening gives a crown with a single middle block, and an even opening gives a crown with two. That one difference settles more of an arch design than the block palette does.

On an odd width the middle block of the crown is the natural keystone: swap it for a contrasting block and the arch has a focal point for free. On an even width the crown has a two-block centre, which lines up with a double door or a two-wide path without any fudging. On odd openings the crown is 3 blocks long up to 5 wide, 5 long from 7 to 15 wide and 7 long from 17 to 21. On even openings the crown is 4 blocks long up to 10 wide and 6 long from 12 to 20.

4 wide  (circle 6, 3 rows, 10 blocks)
.####.
##..##
#....#

6 wide  (circle 8, 4 rows, 10 blocks)
..####..
.#....#.
#......#
#......#

8 wide  (circle 10, 5 rows, 14 blocks)
...####...
.##....##.
.#......#.
#........#
#........#

10 wide  (circle 12, 6 rows, 16 blocks)
....####....
..##....##..
.#........#.
.#........#.
#..........#
#..........#

Turn on Highlight Center in the generator and it draws the centre lines through the blueprint, through a single block on odd diameters and through a 2×2 on even ones. It is the same centre-line habit that stops a big circle drifting by a block, and on an arch it tells you which column the keystone goes in before you have placed anything.

When a half circle stands too tall, flatten it

A round arch rises about half its span, so a 13-wide arch needs 8 rows of wall above the pillars. When the wall does not have that, cut the arch from the top half of an oval instead. Switch Force Circle off on the circle page, or open the oval generator, set the width to the opening plus 2, and set the height to twice the rise you can afford, minus 1.

Over a 9-block opening, an 11 × 7 oval gives a 4-row arch of 13 blocks, against 6 rows and 15 blocks for the full half circle. Flatten it further and the crown stretches: the 11 × 5 version has a crown seven blocks long, and at 23 × 9 it is eleven. Past a point that stops reading as an arch and starts reading as a lintel with rounded shoulders, which suits a bridge deck or a wide window better than a gate.

Pointed arches are two arcs of a bigger circle

A pointed Minecraft arch is two circle arcs leaning on each other, and each arc comes from a circle about twice as wide as the arch. For a 9-block opening, generate a 21-block hollow circle, keep its upper-left quarter as far in as the sixth column, and mirror that onto the right-hand side. The result is 19 blocks over 10 rows, four rows taller than the round arch over the same doorway.

9 wide, pointed  (10 rows, 19 blocks)
.....#.....
....#.#....
...#...#...
..#.....#..
.#.......#.
.#.......#.
#.........#
#.........#
#.........#
#.........#

The general version: the source circle is 2 × (opening + 2) − 1 blocks across, and you keep (opening + 3) ÷ 2 columns of it, counting from the left edge.

At 7 and 9 wide the two arcs meet in a single block. At 5, 11 and 13 they meet in a flat tip three blocks wide, and one more block set on top of it by hand finishes the point. Mark the quarter you are keeping by clicking its blocks, the same way as the round arch, because on a 29-block circle it is easy to lose your place.

I am not sure this construction is the right one below 7 wide. Over a 5-block opening it stands 6 rows tall, taller than the doorway is wide, and looks more like a steeple than a door. I have also only worked it through for odd openings. On an even opening the centre of the source circle falls between two blocks, and I have not found a version I would put in a table.

Depth, thickness and arcades

One arch profile is one block deep. A doorway through a 3-block wall needs the same profile three times, so multiply the count by the depth of the wall: the 9-wide round arch is 15 blocks per layer and 45 through a 3-deep wall. Carry the same profile down a corridor and it becomes a barrel vault, built one identical layer at a time.

For a heavier ring, set Border Thickness to Thick and add 4 to the opening instead of 2. A 9-wide opening then takes a 13-block circle, and the arch is 36 blocks over 7 rows.

A run of arches, whether a cloister, an aqueduct or the outside of an arena, turns on a different number: the bay, which is one arch plus the column beside it. The colosseum build goes through dividing a wall’s block count into whole bays so the row closes without a squashed arch at the far end.

The circle and oval generators plot full blocks only, so smoothing a curve with stairs and slabs is hand work. Dedicated arch generators exist, and if you want that smoothing worked out for you, that is the kind of tool to look for. Reading rings off a blueprint goes further than doorways, though: the round roof guide stacks shrinking circles into cones and domes with the same per-size counts.

Up one and in one still builds a triangle. The rows in the table are what Minecraft arches look like once something has done the rounding for you; set your opening plus 2 in the circle generator and the crown for your width is there to copy.