Option 1: Most Accurate Way (Highly Advise Using this Method)
Lay your current belt flat on a smooth surface and measure it from where the buckle attaches to the leather (the fold) to the current hole used. Order that belt size (round up, if you measure odd). For example if you measure 37" or 38" to the hole you use, order a 38" belt size. It doesn't matter if you wear your belt in the last hole, we will make your new belt measure to the center hole.