How To Measure Your Bra Size

80% of women wear the wrong bra size. Yes, that’s right. That sure is a lot of women wearing the wrong bra! There is obviously a lot of confusion out there about how to measure your bra size. Not only is wearing the wrong size uncomfortable, but it also leads to bad posture and an overall unflattering shape.

Don’t worry. In this article, we’ll show you how to find the perfect fit so you can show off those beautiful curves.


What You Need

To find the right bra size, we’re going to need 3 things. 

  1. Tape measure
  2. The best-fitting non-padded wired bra
  3. Pen and paper to write down your measurements

Are you now all set? Let’s go!


How to Measure Your Bra Size

Step 1: Determine your band size.

Wrap the tape measure around your rib cage, positioning it under your bust. Make sure the measuring tape is snug but not dig into the skin. Now that you have the measurement, round it to the nearest whole number. If the number is even, add 4 inches. If the number is odd, add 5. Example: If your band size is 31, which is an odd number, add 5. So your band size is 36.

Step 2: Measure Your Bust Size.

Wrap the tape measure from behind over to the fullest part of your breast and ensure that the tape is parallel to the floor. This measurement is usually across the nipple. Make sure that it rests comfortably around your breast and that it’s not too tight or loose.

Step 3: Find your cup size.

Okay, we’ll need a bit of calculation in this part. But no worries! We still got you covered. Bust size minus band size equals your cup size. As simple as that. For example, if your bust size is 38 inches and your band size is 36 inches, then 38-36=2. Based on the chart below, you are a B cup.

Note that this chart uses US cup sizes.


Your BRA SIZE is your band size plus your cup size. Example: 36B 


How to Choose the Right Ultra Boost Size

Now that you have measured your bra size, please take a look at the table below to choose the correct size for your BOOMBA inserts. We recommend sizing up in your bikini to accommodate for the boobage (BOOMBA insert). 

Please note that Demi Boost, Perfect Boost and Invisible lift are one size fits A to D while Ultra Boost Inserts come in different sizes.

Bra Size
US 32
AU 10
EU 70
FR/ES 85
US 34
AU 12
EU 75
FR/ES 90
US 36
AU 14
EU 80
FR/ES 95
US 38
AU 16
EU 85
FR/ES 100
US 40
AU 18
EU 90
FR/ES 105
D C D E F Not Recommended
DD/E D E F Not Recommended Not Recommended
DDD/F E F Not Recommended Not Recommended Not Recommended
DDDD/G F Not Recommended Not Recommended Not Recommended Not Recommended

How to Know If You Have the Right Bra Size

Once you’ve figured out your correct bra size, how do you know that it’s right? There’s only one way to find out. Test it! Make sure you try on different bras from different brands, as sizes can differ between brands.

Here’s a bra checklist:

  • The straps should stay on your shoulders and not pinch or dig in your skin.
  • The band should be snug enough but not too tight.
  • The underwire should sit comfortably under your bust.
  • The area between the cups should be flat, and only one finger can slide underneath it. Otherwise, it’s too loose.
  • The cups should fully cover your bust with no spillage on the sides or over the top.

With this information on hand, you can then confidently shop for any of the BOOMBA products. If you are still unsure, please send us an email or DM us and we would be glad to help.


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