HOW TO USE OUR MEN'S SIZING GUIDE
Use the measurements to determine your size. If you're on the borderline between two sizes, order the smaller size for a tighter fit or the larger size for a looser fit. If your measurements for chest and waist correspond to two different suggested sizes, order the size indicated by your chest measurement.
Additionally you can orientate on your height and weight.
HOW TO MEASURE (MEN'S)
Measure the full circumference on chest, waist and hip. The best way to do is using a measuring tape.
Measure around the fullest part of your chest. Keep the measuring tape horizontal.
Measure around the fullest part of your waist.
Measure around the fullest part of your hip.