Work out quilt fabric cutting instantly with clear inputs, formula shown and shareable results.
Block counts round up in each direction, and each block is cut at the finished size plus twice the seam allowance so the seams consume the extra. Seam allowance is added on both sides of every block, so a 15 cm finished block cut at 16.5 cm loses 1.5 cm to the two seams that join it.
Block grid
columns = ceiling(quilt width / block size); rows = ceiling(quilt length / block size)
Cut size
cut = finished block size + 2 x seam allowance
columns = ceiling(quilt width / block size); rows = ceiling(quilt length / block size). Block counts round up in each direction, and each block is cut at the finished size plus twice the seam allowance so the seams consume the extra.
Seam allowance is added on both sides of every block, so a 15 cm finished block cut at 16.5 cm loses 1.5 cm to the two seams that join it.
Enter finished quilt width, finished quilt length, finished block size, seam allowance. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.