A woman's breasts change significantly over time, particularly during and after pregnancy. Weight loss, gain and monthly cycle variations can also have an effect on the fit of your bra. It is advised that you check your bra size once or twice a year.

How to do it.

Traditional Measurement method.

• Try to get someone to take the measurements for you - your posture will be more relaxed and natural. The measurements should be more accurate.
• Stand up straight and breathe normally
• Don't measure over the top of clothing
• Wear the bra you feel most comfortable in
• Use a cloth tape measure if possible

Determining your Bra/Band size

1. Measure around the chest directly under the breast at a constant height with the cloth measuring tape. Add 5 inches to that measurement. This dimension is your bra/band size (If the bra size works out to an ODD number go up one inch to the next EVEN number)
2. Measure around the chest at the height of the fullest part of the breast. The measuring tape should be held horizontal, flat on your back, and your arms should be down.
3. To determine the proper Cup Size, find the difference between step 2 and step 1 (step 2 - step 1.) Use the chart below to determine your Cup Size.

1. Measure around the chest directly under the breast.
2. Measure around the chest, directly above the breasts/under the arms.
3. If the difference between the two measurements is two inches or less, use the Traditional Method. If the difference is over two inches, you may want to try one bra/band size larger for comfort. This will be your bra/band size.
4. If the under-breast measurement is an odd number, add one to reach the next even numbered bra band size.
5. Now measure around the chest at the height of the fullest part of the breast. The measuring tape should be held horizontal, and your arms should be down. Make a note of that measurement (only used for comparison.)

• "Slender" build: A cup
• "Average" build: B cup
• "Heavier" build: C cup

Bra band sizes 40-42:

• "Average" build: B cup
• "Heavier" build: C-D cup

Bra band sizes 44-46:

• "Average" build: C cup
• "Heavier" build: D-DD cup

Important Notes:

• If you are in between sizes or you are having difficulty finding a good fit, when you go up a cup size, you should go down a band size. If you go down a cup size, you should go up a band size E
  
  Example:
  if you have a 36C and it is not fitting quite properly, you would probably want to try a 38B or a 34D)
• When sizes are DD and above, great care must be taken to be properly fitted. Some bra manufacturers make their Bra Size slightly large. (example: a bra marked 38 will probably fit a 40 woman.)
• For sizes above D, cup sizing is not well defined. It can keep increasing by an inch for each successive letter, or it can repeat letters for new cup sizes above D. So, a DD cup is the same as an E cup. A DDD=EE=F cup, a DDDD=EEE=FF=G cup and so on.
• Long line and 3/4 bras should only be considered if their length is LESS than the distance from the under-bust to the natural waist line.
• If either of the bra sizes given here is very different than what you are currently wearing, go with your current size.
• If you are taking these measurements without wearing a breast form on for only a single prosthesis, determining the bra cup size can be more difficult. Some experimentation may be necessary.
• If you are taking these measurements for two prostheses, you can simply take the bra size measurement (Step 1) and then choose the cup size that is right for you.
• These are guidelines only. Proper sizing may vary for different body sizes, heights, and weights.