I made a smaller one, just out of scraps for a baby quilt. I figured I needed 24 strips at 36 inches to give be a 36 X 48 quilt top. the length I wanted was 48 inches, I used 2 1/2 inch strips, so I divided that by 2 and got 24 strips. so multilpy 24 X 36= 936 inches I needed... so from there figure how wide you want it ( my 36 inch) by how long you want it ,size of finished strip, mine was 2 inches, time length you want(which if using 2 1/2 inch strips would be divided by 2) this should work... boy, I sure hope this is clear as mud. I have reread it 5 times and I still understand it. but you know how that can be. Vicki