For all chest measurements, the measuring tape will go all the way around your torso (wrap it around your back and chest).
Don't look down at the tape to take your measurement. Find a mirror to view your reading to; looking down may cause the tape to slip.
Under arm measurement: the goal is to find the measurement for your chest just below were your breast tissue begins (this is usually above the nipples). Ideally, the tape should be at the beginning of your breast tissue and just below your arm pits.
Largest part of chest: the goal here is to get the measurement around the torso and chest where the most breast tissue is (usually around the nipples).
Under chest: the goal here is to get the measurement around your sternum; measure directly under the breast tissue, as high up as possible.
Tip: Always round your number up if your measurement happens to read at any fraction greater than 1/4".
Example: If you measurement reads 36 3/4", round up to 37". Do not round down.
Place the measuring tape at the point of one of your shoulders. Then stretch the tape to the point of your other shoulder. Don't wrap the measuring tape all the way around your shoulders for this measurement-just point to point.
Tip: Try to stand up straight, adjust your posture so that your shoulders aren't hunched, but are still relaxed.