6.5 is the full length of the peplum I worked with,as you saw, the peplum stopped at the hip area, for example,you might want yours to go a bit lower or so. In other words it's my desired length for the peplum. I chose to make mine 6.5, yours can be 10,15,10.5,15.5 as the case may be, so assuming it was a normal material, the half inch would serve as the folding allowance at the hem, and 6 will automatically be the final length. I hope you understand now, thanks for engaging Always feel free to ask your questions