Most men wear shirts on a daily basis and most of them are used to buying shirts after size – S, M, L, XL, etc. But remember that the open collar, sleeve length and shoulder width are equally important.
Decide what you want to buy. The first step is choosing the material. Polystyrene is no longer fashionable for some time, so a cotton shirt is the best choice – not only allows skin to breathe better, but cotton looks much better on the body than any other synthetic material.
Determine the size of your chest. This is the most important step and probably the one most often measured wrong. Most likely all of the shirts you own are a size (maybe even two) higher than they should be. It was fashionable to wear bigger shirts a few years ago, but now things have changed and you no longer need to wear a shirt that looks like a tent. Also, another important factor in choosing a shirt is a comfort. Be careful not to choose items that you are too small because they are uncomfortable and hold you when you move.
A little trick to convince you if you made the right choice: when you tuck your shirt in your pants, does it sit puffy above the belt? If so, it is not the right size.
Make sure it is not too tight on the neck. Any quality shirt has neck measurement stated on the label, but if not, you should be able to put three fingers (no more, no less) between the collar and neck when all buttons are closed.
Sleeve length is important. If you want to wear a shirt without a vest or jacket, then cuff should end just below the wrist bone. If you want to wear it with a jacket, the sleeves must be even longer, approximately 1 inch below the wrist. This will allow some of the cuffs to be seen even with the jacket on. Make sure that when you stretch your arms in front, sleeves of both shirt and jacket do not exceed wrist (if you want to wear a jacket).