Setting triangle formulas
- Side setting triangles: cut square = finished block × 1.414 + 1¼". Cut each square twice diagonally (an X) to get 4 triangles.
- Corner setting triangles: cut square = finished block ÷ 1.414 + ⅞". Cut each square once diagonally to get 2 triangles. Two squares give all four corners.
- Finished width of the center: blocks across × finished block × 1.414.
Example: 8" blocks. Side triangles: 8 × 1.414 + 1.25 = 12.56", rounded up to 12⅝". Corner triangles: 8 ÷ 1.414 + 0.875 = 6.53", rounded up to 6⅝". A layout 4 blocks across is 4 × 11.31 = 45¼" wide before borders.
Setting triangle chart
Exact cut sizes rounded up to the nearest ⅛". Add 1" to each if you like to trim.
| Finished block | Block on point | Side triangle square | Corner triangle square |
|---|---|---|---|
| 4" | 5⅝" | 7" | 3¾" |
| 5" | 7⅛" | 8⅜" | 4½" |
| 6" | 8½" | 9¾" | 5⅛" |
| 8" | 11⅜" | 12⅝" | 6⅝" |
| 9" | 12¾" | 14" | 7¼" |
| 10" | 14⅛" | 15½" | 8" |
| 12" | 17" | 18¼" | 9⅜" |
| 14" | 19¾" | 21⅛" | 10⅞" |
| 16" | 22⅝" | 24" | 12¼" |
Assembling an on-point quilt
- Sew the quilt in diagonal rows, with a side triangle at each end of a row, then join the rows.
- Add the corner triangles last. They're cut slightly large, so center them and trim.
- Handle the triangles by their short edges; those are on the bias and stretch.
- Adding borders or need a bed size? Try the quilt size calculator.