How to calculate bra measurements

Updated April 17, 2017

Determining your bra size can be a confusing task since there are so many inaccurate ways measure and calculate it. Many women opt to be measured by a professional in lingerie and underwear stores like Victoria's Secret, but this can be embarrassing, especially if you're told that you're wearing the wrong size. Instead of having someone else calculate your bra size, follow these steps to learn how to properly measure and calculate your bra cup and band size yourself.

Measure the circumference of your chest just above your breasts. Wrap a roll of soft measuring tape around your upper chest just below your armpits. Stand in front of a mirror to make sure that the tape is straight in the back and does not slope down or up. Write down the measurement in either inches or centimetres and round up if the measurement falls between numbers. For example, if your upper chest measurement is 32.5 inches, round up to 33.

Measure the circumference around the largest part of your breasts. This measurement is usually taken over the nipples since that is the largest area of the breast. Make sure not to hold the measuring tape too tightly over the nipple area; the tape should lie flush with your bra. Record your measurement in inches and round up if necessary.

Measure just below your breasts and record the value. Wrap the measuring tape around your rib cage, or just below the bottom of your bra. The tape should feel snug against your skin but not too tight. Write down the measurement and add 4 inches to it if it's an even number and 5 inches if it's an odd number. For example, if you measure at 30 inches, your actual measurement will be 34 inches.

Subtract the step 3 measurement from the measurement in step 2. For example, if your measurement in step 2 is 36 inches and your measurement in step 3 is 34 inches, you will have 2 inches left over.

Subtract the measurement in step 1 from your measurement in step 3 and add it to your new measurement in step 4 to calculate your bra size. For example, if your measurement in step 1 is 33 inches, and your measurement in step 3 is 34 inches, you'll have 1 inch left over. Add this to your leftover inches from step 4 to get 3 inches. Bra cup sizes are usually calculated as 1 inch equalling an A cup, 2 inches equalling a B cup, 3 inches equalling a C cup and 4 inches equalling a D cup. Since there are 3 inches remaining, your resulting cup would be a C. Your band size equals the measurement in step 3, so if your measurement is 34 inches, your bra size would be a 34D. To double-check your results with an online calculator and learn more about bra sizing and calculations, go to


Wear a comfortable, nonpadded bra while measuring for accurate results. Do not inhale or exhale during measuring. This will result in false measurements and possible improper bra sizing.

Things You'll Need

  • A comfortable, nonpadded bra to wear while measuring
  • Soft measuring tape roll (also known as sewing tape)
  • Pen and paper to record measurements
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