On Point Quilt Calculator
Blocks set on point are turned 45° and filled in at the edges with setting triangles. Enter the block size and layout to get the finished size, the block count, and exactly what to cut for the triangles.
On Point Quilt Calculator
Set the finished block size and how many whole blocks sit in the top row and down the side. You get the diagonal, the finished quilt size, the number of blocks, and the setting and corner triangle cuts.
Formula: diagonal = block × 1.414; side triangle square = diagonal + 1¼", cut twice diagonally; corner triangle square = block ÷ 1.414 + ⅞", cut once diagonally
Results
Finished Quilt Size
67⅞" × 84⅞"
172 × 216 cm, before borders.
- Blocks
- 32
- Diagonal of one block: 17".
- Side Setting Triangles
- 14
- Cut 4 squares 18¼", then cut each twice diagonally (4 triangles each).
- Corner Triangles
- 4
- Cut 2 squares 9⅜", then cut each once diagonally.
- Setting Fabric
- 1 ⅜ yd (1.3 m)
- Side and corner triangles together.
Cut setting triangles as instructed so the straight grain runs along the outside edge — the quilt will not stretch out of shape. Many quilters add ½" to the triangle squares and trim the edge afterwards.
Turn a photo into a real pattern
Upload a photo or drawing and get an embroidery pattern for the centre block or a quilt label.
Open Embroidery GeneratorSetting Triangle Chart
Side triangles: cut the square twice diagonally. Corner triangles: cut the square once diagonally. Sizes rounded up to the next ⅛".
| Finished block | Diagonal | Side triangle square | Corner triangle square |
|---|---|---|---|
| 4" | 5.66" | 7" | 3¾" |
| 6" | 8.49" | 9¾" | 5⅛" |
| 8" | 11.31" | 12⅝" | 6⅝" |
| 9" | 12.73" | 14" | 7¼" |
| 10" | 14.14" | 15½" | 8" |
| 12" | 16.97" | 18¼" | 9⅜" |
| 14" | 19.80" | 21⅛" | 10⅞" |
| 16" | 22.63" | 24" | 12¼" |
How On Point Math Works
Turned on point, a block is measured along its diagonal: finished block × 1.414. A 12" block is 16.97" corner to corner, so four blocks across make a quilt about 68" wide.
An on-point layout with 4 blocks across and 5 down has 4 × 5 whole blocks in the outer rows plus 3 × 4 in the rows between them — 32 blocks. The gaps along the edges take 2 × (4 − 1) + 2 × (5 − 1) = 14 side setting triangles, and the corners take 4 corner triangles.
Side triangles are cut from a square of diagonal + 1¼", cut twice diagonally, so the long edge of each triangle is on the straight grain. Corner triangles come from a square of block ÷ 1.414 + ⅞", cut once, so their two short edges are on the grain.
Oversize, Then Trim
Many quilters add ½" to both triangle squares and trim the quilt edge after assembly, ¼" beyond the block points. It forgives small piecing errors and lets the blocks float slightly off the edge.
On Point Quilt FAQ
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