Correctly measuring your pectoral muscles is essential to determine the right fit for a men's dress shirt or suit jacket. If you want to increase your chest size, measuring its circumference can help you keep track of your progress. Your measurements can indicate whether your exercise routine and diet are effective. To get the most accurate progress overview, measure yourself in a similar manner each time.
Remove your top so your chest is bare. Measuring over bulky clothes can add inches and give a wrong indication of muscle growth. If you're measuring yourself to determine your jacket or shirt size, measure over a well-fitting shirt.
Stand in front of a mirror that allows you to see your chest so you can see what you're doing and ensure that the measuring tape isn't twisted. Avoid flexing your muscles or sticking out your chest -- maintain a relaxed stance.
Wrap a flexible fabric or plastic measuring tape around the widest part of your chest. Start at the front of your chest and work your way around, going just below your armpits and under your shoulder blades. Alternatively, have a friend take your chest measurement so you can keep your arms down and slightly away from your body.
Keep the measuring tape snug and parallel to the floor. Avoiding pulling it too tight, because this might result in an inaccurate measurement -- it shouldn't be digging into your skin.
Read the measuring tape and write down your chest measurement for future reference.
Tips
Avoid measuring pectoral muscles after working out. If you train your chest beforehand, blood flow to the muscles increases, resulting in an inaccurate measurement.