The sizing tips tab is pretty helpful as well. If you look at both of them, you should have a VERY good idea of what size to get.There are measurements at the HPA website:
History Preservation Eastman German Luftwaffe Flying Jacket | History Preservation
Eastman's WWII Luftwaffe Leather Flying Jacket is a stylish design of versatility that will serve you as faithfully as the German pilots did the Luftwaffe.www.historypreservation.com
Look under the product measurements tab where the average of many jackets for each size is given. I've never tried one on, or actually seen one in person, however. Hopefully, others with first-hand experience can provide more information.