Bra Size Calculator - Find How to Measure Bra Size
Bra Size Calculator
Shopping for the right size bra is always a difficult task. Without determining the bra size, one would mostly end up purchasing the incorrect size. Tight or loose straps, big or small cups cannot be worn regularly and becomes an obstacle to our work. This is where sister size bras come to the rescue.
Bra Sister Size Chart – How It Works
Sister sizes are alternate sizes where the cup volume stays the same even when the band size and cup letter changes. Using a sister size bra is effective as it fits more perfectly for women who feel uncomfortable wearing the original size bras. In a sister size bra, the bra cup sizes are denoted as letters (A, B, C or D) and the band size as numbers (32, 34 or 36).
With the bra measurements handy, it is easy to choose the ideal sister bra size and the best method would be to go for the nearest sizes. Check out Shyaway’s bra size chart for determining your accurate breast size.
You can size up if the bra feels tight even while wearing it in the loosest hook, and size down the bra when it feels loose even while wearing it in the tightest hook.
Example for sister size up - 34C to 36B
Example for sister size down - 34C to 32D
Things to remember:
The band fits but the cups don’t - Go up or down for your cup with respect to your size.
The cups fit but the band doesn't - Go up or down for your band size and make sure which is comfortable for you.
When going up with the back size one should go down with the cup size to keep it the same as the current bra size. Accordingly, while going down with one's back size, one should go up with the cup size to keep it the same.
Sister sizes can help women discover the right fit for their comfort. Wearing a bra with the perfect bra size makes one feel empowered and also boosts confidence. So make sure to get the right sister-size bras!
Importance of Wearing the Right Bra Size
It is necessary for women to wear the right bra size as a woman’s comfort relies on it. Bra fitting the woman perfectly can increase confidence, reduces discomfort and prevents bulges and sagging.
How to Find The Perfect Bra
Around 80% of Indian women wear ill-fitting bras- this is a known fact! An ill-fitting bra not only destroys your outlook but also doesn’t give you the needed support, the straps slip or dig in, cups overflow and also causes health related problems.
Knowing your correct bra size is the best way to find the perfect bra. So make use of this guide on online bra size calculators to get the right one.
How to Measure Bra Size?
It is important to know the women's breast size for choosing the right bra, fitting them. Follow the steps below to determine women bra size, which includes the band size and the cup size.
Bra Size in cm
One can check their bra size in cm by following the below steps to take your accurate bra measurements.
Band size: Take a measuring tape, and turn it towards the cm side. Place the tape under your bust and measure the circumference under your band. This would be your Band Size.
In Shyaway, your Band size will be determined in Inches - even if you have measured your bra size in cm, mentioned as 32, 34, 36, etc. If your measurements are in between, like 28.3, it is advised to round it off to 29. Rounding off your measurements to the nearest even number will help you find the right size.
Bust size: Bust size in cm are indicators of cup sizes. To measure the right bra size in inches, wrap the measuring tape over the highest part of your bust (usually the nipple area) and hold the tape in a comfortable position. The tape should not be too tight or too loose. Once the tape is held in a proper, comfortable position, measure the size and round off to the nearest whole number. If your measurement is 31 inches, make it 32 (not 30).
Shyaway helps measure your bust size in inches - measuring bust sizes are a bit tricky as the sizes vary widely in women. Usually, the highest part is the nipple area in most women but it might vary a little depending on a woman’s natural bust shape. So be careful while determining the highest part of your bust as it tends to vary. Once you have found the highest part of your bust, it will be easier to measure your bust size.
How to Measure Bust Size
Step 1:
- Wrap the measuring tape around the fullest part of your bust.
- Wear a regular, non-padded bra while taking the measurement.
- Make sure that the tape is not too tight or too loose- just place it smoothly at the nipple level.
- Record the measurement and round off to the nearest whole number.
How to Measure Band Size
Step 2:
- Stand straight and bring the measuring tape around your torso.
- The tape should fit snugly around your band. Not too tight or too loose.
- Record the measurement obtained and round off to the nearest whole number.
- Now, subtract the band size from the bust size we calculated earlier.
Follow the instructions correctly to find your correct size. Knowing your size is important for your physical health and your glam. Check your bra size every 3-6 months. We at Shyaway pave you the most effective way.
Calculate Your Cup Size
With your Band and Bust Size measurement in hand, you can use the formula to determine your Cup Size,
Cup Size = Bust Size - Band Size
Every inch difference will denote a cup size. A difference of 1 inch denotes A, a difference of 2 inches denotes B, and so on. Here’s a table below for your reference.
Shyaway brings you a wide collection of stunning lingerie, available in different bra sizes. Explore the wondrous collection and shop your favourites at pocket-friendly prices.
How to Measure Bra Size Without Measuring Tape?
One can check their bra sister size at home, even without a measuring tape. Follow these steps to determine one bra size:
- Use a string or a cord in place of a measuring tape.
- Wrap the string around the bust - first under the bust line, then on the bust line.
- Take a note of the length with a pen.
- Determine the correct dimensions using a folding ruler.
Using the measurement of the ruler, one can determine their bra size. Even though one can successfully measure bra size without a measuring tape, sometimes the measurements might end up being incorrect. So it is advised to use a measuring tape or visit a nearby lingerie store to get the right measurements. Check out Shyaway’s bra size calculator to determine your accurate bra size in inches.
I Want to Know My Sister Size
Though each bra size has four sister sizes, you should choose the closest two when shopping for sister-size bras.


Sister Size Up
If your bra size is 34C, your sister's bra size will be 36B. (One band size higher and one cup size smaller).
Sister Size Down
Similarly, if you're a 34C, your cup size will be 32D. (One band size lower and one cup size bigger)


Should I Definitely Opt for Sister Size Bras?
1. Please keep in mind that a size bra may not fit you for a variety of reasons. Make a note of which aspects of your bra need to be adjusted to attain the best fit. This will assist you in finding a bra that fits properly.
2. It's also crucial to recognise the physical changes in your body that could lead to a mismatch. During puberty and pregnancy, your usual bra will not suffice. So, in this case, trying sister sizes would be the best solution.
3. Furthermore, an ill-fitting bra can cause a great deal of discomfort, as well as neck and shoulder pain and posture issues. As a result, rather than going with the same uncomfortable bra, you could go for sister sizes.
4. If you are still unhappy with the sister sizing concept, we propose that you measure yourself for the correct bra size before continuing your buying.
Tips on How to Buy the Right Bra for You
With the right bra size in hand, it’s time to choose the lingerie that would suit you. Here are some important tips on how to buy the right bra for you:
- Decide on what type of bra you want.
- Plan your budget accordingly.
- Try on your lingerie before buying it. If you happen to purchase online, then make sure you determine the right bra size.
- Modify your bra if necessary - like adjusting your straps, adding a clip to hold your straps together.
- Look out for different bra styles and fabrics for preferred comfort.
Bra Size Calculator FAQs
1. Why do you add 4 inches to your band size?
You can determine your bra band size by adding four inches to your band size. Subtract your bust size from your acquired bra band size to get your cup size. For example, if your band size is 30 inches and your bust size is 36 inches, adding four to the band size (4 + 30) gives 34 inches.
Subtracting bust size from band size (36 - 34) gives 2 inches. This 2 inch represents the letter B as cup size.
2. What is cup size A, B, C, and D?
Bras are available in different sizes. Letters A, B, C, and D denote cup sizes. Numbers like 32, 34, 36, and 38 are measurements of underbust called band size. The cup size indicates the volume of the bust and as the letters increase, the cup size also increases.
Example: Bra size 34B indicates that your boob is a B cup and your bra is 34 inches around.
3. Are bra size and bust size the same?
Bra size and bust size are not the same. Bra size is determined by two measurements, the band size, and cup size. Whereas your bust size is the difference between chest size and bust line measurement.
4. Will bra increase breast size?
No, a bra will not cause or prevent breast growth. It is determined by a woman’s genes and hormones, not by her bra. Wearing the correct size bra makes you feel more at ease. A smaller bra causes breast pain due to compression, while a larger bra provides insufficient support and causes bouncing.
5. How will my bra size change during pregnancy?
During pregnancy, a hormone called relaxin is released, which loosens your ligaments and allows your bone to structure to accommodate the growing baby. These ligaments when combined with an increase in fluid in the body, increase the band size of the women.
6. What is the difference between cup size & bra size?
Bra size is obtained by measuring the band size and the cup size. On the other hand, cup size doesn’t represent breast size, but instead the difference between the rib cage and the bust.
7. What are sister sizes?
When a standard bra size chart doesn’t provide an accurate measurement, one can choose sister sizes. Essentially, these are alternate bras with constant cup volume but the band size and cup letter change. For instance, if you are a 34 B, a bra size like 32 C or 36 A will mostly fit you. 32 C has a shorter band size and 36 A has a longer band size, so you can choose the one which fits you the best.
8. What happens if you wear the wrong size?
Wearing the wrong bra sizes leads to the following health issues, including
- Breast tissue pain and discomfort
- Backache, neckache, and headache
- Poor posture
- Your bra restricts your posture.
- Work hard to support the weight of your breasts.