Resize Quilt Block Calculator
Enter the pattern's block size and the size you want. You get the new cut sizes.
How the resize quilt block calculator works
To resize a block, scale the finished sizes, not the cut sizes. Seam allowances stay 1/4" no matter how big the block is.
For grid-based blocks, divide the new block size by the number of grid units across. That is each unit's finished size; add 1/2" for the cut size. For any single piece from the pattern, the calculator subtracts the 1/2" seam allowance, scales the rest, and adds the 1/2" back.
The scale percentage is what you would set on a copier to resize a paper-piecing or applique template.
Questions
How do I resize a quilt block from 12 inches to 6 inches?
Every finished measurement is halved. A 4 1/2" cut square (4" finished) becomes 2 1/2" cut (2" finished). For printed templates, copy at 50%.
Why not just scale the cut sizes?
The 1/4" seam allowance doesn't change. If you scale a cut size directly, the seam allowance shrinks or grows too and the block comes out the wrong size.
Which block sizes resize cleanly?
Sizes divisible by the grid count. A nine-patch works best at multiples of 3 (6", 9", 12"). A four-patch works at any even number.