When making a d9p how do you figure what size of a nine patch you need to get the finished size of block you want after you cut and resew your pieces. Hope that makes sense. Thanks in advance to all you math savvy quilters.

If I am starting out with a 9 1/2" unfinished block (3 1/2" squares) and you cut it twice, you will lose 1/2" both ways and end up with a 9 inch block, 8 1/2" finished.

If you cut each square at 3 5/8 inches (1/8" larger), your overall block will be 1/8" too big. You could then square it up and shaving that little off each side (1/16") would not be noticeable. And you would end up with a 9" finished block.

So you could add 1/8" to any sized 9 patch square, slightly trim and get the finished size that you want.

That makes sense. I did have to "shave" my sides for my finished block. This board has so much info thought someone may have ran across the exact measurements for before and after. Thank you - will give it a try.

I used charm squares for mine and the block ended up at 12 inchs finished. Thats in the finished quilt.

that block is on my to do list.

Refresh me - what size is a charm square?

Charms are usually 5" squares from a whole fabric design collection, although I have seen them 4".

Thank you. Will do some figuring and trial blocks.

I order charms alot and I cut up my scraps to 5 inchs. So much you can do with them and they are perfect for D9P.