For the best fit, just buy one size larger than your waist. For example, if you are a size 36' waist then choose a 38' belt. On each belt page, you may click on the Sizing Chart picture, and there is a chart showing the measurement to the center hole of the belt. Compare your measurement to that and order that size. If you are in-between sizes, then round up. To measure a belt, measure from where the buckle meets the leather to the hole you are wearing the belt in comfortably.