Belt Size Guide
A general rule of thumb for sizing is to take your pant size, and add two to the sizing. A size 30 pant should get a size 32 belt, for example. The best way to find your belt size, however, is to measure a belt that you have worn regularly.
When measuring your belt, measure from the "fold" at the front (where the belt attaches to the buckle) to the hole/length most used. Ideally, the length most used will be in the middle of the size range to allow room to adjust on days you need to without it being uncomfortable.
Another factor that can impact the size of the belt is where you decide to wear the belt. Around the hips will provide a size closer to the actual pant size, while around the waist or between the hips and waist will provide a size closer to the shorter end of your range.