Originally Posted by Holice
However, remember if you are enlarging a pattern, you should enlarge the finished size of the piece/shape without the seam allowance. Then add the seam allowance because otherwise the seam allowance will be too large.
EXTREMELY IMPORTANT POINT!
Example: 2 x 4 finished piece is cut 2.5 x 4.5
If one wanted to make a 4 x 8 finished piece, one would cut a 4.5 x 8.5 piece, not a 5 x 9 piece.