How many finished blocks fit your quilt top.
Assumes no sashing between blocks. Add sashing width to the block size to plan for it.
The number of blocks that fit a quilt is found by dividing the width and the height by the finished size of each block, using whole numbers. A 60 by 80 inch top with 10 inch finished blocks holds 6 across and 8 down, which is 48 blocks. If the numbers do not divide evenly, change the quilt size slightly or add a border to take up the difference.
Each block is cut and pieced to the finished size plus a half inch for the seams, so a 10 inch block is made at 10.5 inches. Using the unfinished size when you cut helps avoid mistakes in the layout.
Sashing, the strips between blocks, makes the quilt larger and gives the blocks room, so include it in your calculation. A setting with alternate plain blocks uses fewer pieced blocks and is a good option for a large quilt that you want to finish faster.
Plan the arrangement before you sew. Lay the blocks out on a design wall, spread colors and patterns evenly, and sew them into rows and then into the whole top, checking that the rows are the same length as you go.