Originally Posted by colorfulom

If you plan to use the borders Bonnie designed, each side of your quilt needs to end up a multiple of 8 inches, including the inner border. That's because the repeat of the border design is 8 inches (one each of the two slightly different broken dishes units).

Each of the main quilt blocks finishes at 12 inches, and the green sashing strips finish at 3 inches. So if you have 3 blocks wide, that's 3x12=36 for the blocks, plus 4x3=12 for the sashing, so 48 inches before adding an inner border. The next multiple of 8 is 56 inches. So you'd need 8 inches of additional width in this case, so 4 inches of inner border on each side.

If you have 4 blocks wide, that's 4x12=48 for the blocks, plus 5x3=15 for the sashing, for a total of 63 inches. You could either add one more inch to get 64 inches, meaning a 1/2 inch finished border, or you'd need to add 9 inches, by using a 4 1/2 inch finished border.

If I were making a 3x4 block quilt, I think I'd add a 4 inch finished border down the long sides, and 4 1/2 inch on the short sides. Then the outer border should work out all around, and the slight difference in inner border width won't be very noticeable at all.