I followed the sizing chart and instructions VERY CAREFULLY based on all the comments.  I'm a size 4 with a slightly longer than average torso.  I  ordered the L. The sleeve length was a fit. the sleeve width was a bit snug for comfort but technically fit.  The body of the blazer was about 5 sizes too large. (literally, 6+ inches of extra room).  Even more disappointing was the fabric.  No breathability whatsoever.  The picture looks very crisp/structured, but this blazer hangs like sloppy rayon t-shirts from the height of 80s fashion.