By your regular normal size. I thought a large when normally wear a medium I will have to have it tailored. Otherwise it is a beautiful color. The lining is white not off-white or a linen color. I will have to have some tailoring done because the lapel is kind of an odd shape. Otherwise I plan on wearing this to my son's wedding and it gotten great compliments on the outfit with tuxedo pants. Would definitely buy again. Cannot reinforce order your regular size.