I followed the sizing chart for this brand and the shirt was still too small to wear comfortably. I chose the 18 Big and normally wear 3XL. So use that as a point of reference and go up a size or two unless you want the shirt to be rather snug. I prefer they be loose so I can't really wear it. The fabric is ok but not as comfortable as other cotten/poly blends of the same parts that I've worn, including shirts that were cheaper than this one.