Total brain cramp...square in square block
 

I need to make 3” finished square in square blocks. I have found a few different charts online, but they are not working...I have cut the center square 3 1/2”, and used a chart that said to cut 2 3/4” inch squares, cut in half diagonally. Those are too small. Another chart said to cut 3” square, cut diagonally, and those were too large.
I am away from home, and I don’t have scraps to play with. Can anyone help this math-challenged old lady, please?!

Never mind! I was not constructing this correctly...I also need 6” economy blocks, so I was attempting to sew it the same way. I think I just need to “ snowball” the corners. Geesh. Getting old is not for the timid. Haha.

well, even if too large you can always trim them square. better than too small. good luck!

Here's the math I use for any size Square in a Square block: Let's say for a 4" finished block.

large, center square = finished size of block + 1/2" = 4" + 1/2" = 4 1/2"
small corners = finished size, divide by 2 + 1/2" = 4 / 2 = 2 + 1/2" = 2 1/2"