Buying a shirt online can be hard. This page is how HawgDog takes the guessing out.
Grab a shirt you already like the fit of. Lay it flat on a table, face up, and smooth it. Do not measure it on your body.
Measure the chest from armpit seam to armpit seam, straight across. Measure the length from the top of the shoulder, at the collar seam, down to the bottom hem. Use inches.
Open the size chart on the product page. Match your chest number to the Chest row and your length number to the Length row. If you land between sizes, pick the larger one. A riding shirt that is a little long is easier to live with than one that is tight across the chest.
Each garment style is cut differently. The chart on that product is the one that counts. Order the size that matches.
Measure twice, order once!
Fit the material on the 'Fabrics' page. Use this page to pick the size.