Replacement aortic heart leaflets and method of making the same. The replacement aortic heart leaflets of the present invention include first and second segments. The second segment is integral with, and extends from, the first segment. A virtual line L having a predetermined length corresponding to the distance between two known aortic commissures separates the first and second segments. In another aspect of the invention, the first segment has a virtual line AM of predetermined length. In another aspect of the present invention, a leaflet-measuring device is described. In another aspect of the invention, a standard set of replacement aortic leaflets is described. Methods are provided to provide replacement aortic leaflets based on traced outlines obtained from a surgically opened aortic ring.