A QuiltPlan piecing reference
Square in a Square
a floating diamond, no set-in seams needed
A Square in a Square sets one fabric on point inside another: from the front it reads as a diamond floating in a frame. It's the mirror image of a Snowball, sewing a triangle onto all four sides of a plain square instead of clipping the corners, so there's no set-in seam and no Y-seam to fuss with.
Center square: finished size × 0.71, + ½″, rounded up to the nearest ⅛″.
Corner squares: finished size ÷ 2, + ⅞″. Cut two, then cut each once corner to corner.
Example: 6″ finished block
A 6″ finished block needs one 4¾″ center square and two 3⅞″ corner squares, cut into 4 triangles. Read straight off the chart below for any other size.
1 · Cut
Cut two corner squares in half once, corner to corner, for 4 triangles total.
2 · Position
Right sides together, center a triangle's long edge on one side of the square.
3 · Sew & press
Sew a scant ¼″ seam, press the triangle open. Repeat on all four sides.
4 · Trim
Square up through the points to your unfinished size (finished + ½″).
| Finished | Center sq. | Corner sq. |
|---|---|---|
| 2″ | 2″ | 1⅞″ |
| 3″ | 2⅝″ | 2⅜″ |
| 4″ | 3⅜″ | 2⅞″ |
| 5″ | 4⅛″ | 3⅜″ |
| 6″ | 4¾″ | 3⅞″ |
| Finished | Center sq. | Corner sq. |
|---|---|---|
| 7″ | 5½″ | 4⅜″ |
| 8″ | 6¼″ | 4⅞″ |
| 9″ | 6⅞″ | 5⅜″ |
| 10″ | 7⅝″ | 5⅞″ |
| 12″ | 9″ | 6⅞″ |
Same corner-triangle math as Snowball, just sewn to all four sides instead of clipped.
Designed to print. Use your browser's Print (Ctrl/Cmd+P) for a clean letter-size page.