My mom is wanting to make a D4P quilt and I'm trying to help her figure out how much fabric to use, but for the life of me I can't seem to find information about the finished sizes of blocks. I did find that if she were to use 5 inch squares, the block would be 8.5 inches finished. But that is too small of a block for what she is wanting. If she were to use 8 inch or 10 inch squares, how big would the finished block be? Thank you for the help.

For 10" squares, blocks would end up @ 18.5".
For 8" squares, blocks would end up 14.5".

Simple math...subtract 1/2" for initial sewing together of squares.
subtract 1" for resewing after being cut.

therefore, double original square, then subtract 1.5".

Thank you for the help! Now I can plan the quilt for her!

So 7 inch squares will give you a 12 and 1/2 unfinished? I would try 7 and 1/4 and cut down to make the 12 and 1/2 unfinished.

Thank you for asking this question and for all who answered...now I need some information. When using the larger squares to make a larger finished block, is it still cut the same? I believe it is 1 inch on each side of the center seam or maybe use more than 1 inch to make a larger center square so it will be in proportion to the finished square. Thank you

I would increase the width I cut accordingly to match the larger blocks. Do a couple of practice blocks with scraps to see what is visually appealing...