Determine your sports bra cup size

Determine your sports bra band size. Stand in front of a full-length mirror wearing an unpadded bra. Wrap a cloth measuring tape around your rib cage just underneath your breasts, which is where the bottom band of a sports bra typically rests.. Make sure the measuring tape lies flat and snug against your skin. Add 5 inches to the number on the tape measure. If the resulting number is even, then this is your band size. If it's an odd number, add 1 inch. Make a note of this measurement in a small notebook or on an index card.

Determine your sports lingeries cup size. Wrap the measuring tape around the fullest part of your breasts. Take this measurement, and subtract your band size from it. If the difference between the two numbers is 1 inch, then you are considered an A cup. A difference of 2 inches is a B cup, 3 inches equals a C cup and 4 inches translates into a D cup. Make a note of your cup size. Now put your band size and your cup size together and you'll have your bra size. For example, a woman with a 36 band and a C-size cup will need a sports bra sized 36C.

Wrap a measuring tape around your body directly under your bust line. Exhale to release excess air from your lungs; then take the measurements in this area. Ensure the tape is parallel to the ground to get as accurate a measurement as possible. Round the measurement up or down to the nearest inch. Because bras are made with even-numbered band sizes, you'll have to add a number to your measurement. If your rounded measurement is an even number, add 4 inches. If it's an odd number, add 5 inches. The result will give you your band size. This size will change throughout pregnancy.

Wrap the measuring tape around your body, holding it against the apex of your bust. The tape measure should be lightly touching your body, not making an indentation. Take the measurement on the tape and round up or down to the nearest number. Subtract your band size from your bust measurement. This will give you a number that you can use to determine your cup size. If the number is 1 inch or under, the cup is an A, 2 inches is a B, 3 inches is a C, 4 inches is a D, and 5 inches is a DD. This size will change throughout pregnancy.