Square in a Square Calculator

Getting that center diamond to float perfectly

Stitch-and-flip is the easier method for most quilters. No cutting triangles, no fussing with bias edges. Place an oversized square on each corner, sew on the diagonal, trim the excess. Save those trimmed corners — they're bonus HSTs. Sew opposite corners first, press outward, then add the remaining two.

The whole point of this block is that center diamond floating with equal margins on all four sides. Press corner triangles outward after each pair. Then measure: the center square's points should sit exactly 1/4" from the raw edge on all four sides. If it's off, fix it before adding the next pair of corners. Powering through all four and hoping for the best never works.

Trim to exact unfinished size using a square ruler with the diagonal line aligned to your center seams. If the diamond looks off-center after trimming, your corner pieces weren't centered when you sewed — pin at the midpoint of each seam, not just the ends.