SuzSLO

Assuming that the pattern calls for a finished 4.5” (5” cut) center block and you would like to use a finished 6” (cut 6.5”) center block, then the finished size of the complete block will need to increase from 18” (4.5” x 4) to 24” (6” x 4).

If this still interests you, start by getting out the graph paper and draw the finished pattern (not the cut sizes) for one block based on the pattern. Then you will essentially multiply each piece by 1.333 to get the new finished size. You will then need to add 1/2” to each piece to get the cut size.

For example, the 5” square A (4.5 finished) in the pattern will be cut as a a 6.5” square (6” finished) in your enlarged block. That 3 1/8” square (2 5/8” finished) will become a 4” square (3.5” finished). At first glance, your only really trick calculation looks to be those 2.5” squares. A 2” finished square will need to be cut at just a bit more than 3 1/8” so that it will finish at a bit more than 2 5/8”.

Then count the number of blocks (you may want fewer than the pattern calls for since each block will be larger) and the number of each unit in each block. That will allow you to calculate yardage for the pieced blocks. Adjust the borders to match the new block size and calculate that yardage. Use your graph paper to draw a cutting diagram to make sure you aren’t wasting fabric.

Best of luck.