Alternatively, you can measure your waist. Remove any belt you may be wearing. Wrap the tape measure around you at about the level where you intend to wear your belt. Ideally, you should be have on a pair of pants so you you can run the tape measure through your belt loops. Pull the tape measure up as snug as you like to wear your belt. (Some people wear it tight, others want it looser.) That is the measurement you should send us.
Allowing for the buckle The measurement produced by either of the above methods is the size you will order (For men, this will usually 2 inches larger than your trouser size.), unless you will be wearing your belt with an unusual buckle. If the prong of the buckle, where it hooks into the belt, is more than 2 inches from the end of the belt, please subtract from the size of your belt the amount in excess of 2 inches. (Example: if the prong of your buckle is four inches from the end of the belt, subtract 2 inches from the size of the belt you order.)