How to measure yourself for a Bra Lab bra.

Before we start, it’s necessary to emphasize that at the Bra Lab, your bra comes in 3 separate pieces. These separate components give you the best custom fit possible and endless options for styles with just one set of cups.

You have your cups, your back bands and your shoulder straps. If you want to go strapless you can forego the shoulder straps. If you want added convenience you can buy a 2-in-1 back strap that has the shoulder straps already attached. These are a really pretty and easy option.

Bra Lab sizes come in numbers for the cup 1 - 9, and XS, Small, Medium, Large and XL for the back bands. Our shoulder straps are one size and adjustable.

Converting your traditional size to your Bra Lab size

When you’re converting to a Bra Lab bra you need to take your full traditional size and put it into our converter. You will find the converter on the home page when you click on the button that says Build a Bra :


Custom bra converter

So, say you are a 40D. You enter 40 where it says back and D where it says cup. This will give you a number and a letter/size result. For example 6 XL. This means your cup size is a 6 and your band size is an XL.

Once you've converted your bra size into a Bra Lab size of a cup number and a XS to XL back band, then you can continue shopping.

You also have the opportunity to input your traditional bra size if you land on the product pages directly. See below:


Cups page bra converter

 In the past we had a letter system for cups A,B,C,D etc but we found customers would automatically buy their traditional cup size not realising that their cup size in traditional bras is completely relative to the band size. For example, if I’m a 42E my boobies are much bigger than my friend over there with a 32E.

 What if I’m unsure of my accurate size in traditional bras?

Sometimes we find that Bra Lab customers have been wearing the wrong bra for years. We know this from measurements. Have you been wearing the same bra size all your life? Have you been wearing the same bras for years despite fluctuating in weight? If you answer yes to either of these questions, you are likely wearing an ill-fitting bra. Bras that don’t fit well can affect your posture, give you headaches and make you look….well, not as good!

As a fun (and very important) exercise in getting your ideal bra size, we suggest you measure yourself properly. Take a soft strip of measuring tape and stand tall while wearing your best fitting, non-padded t-shirt bra. Make sure your breasts are not drooping (in other words, don’t measure yourself bra-less). Take the tape and measure across the largest point of your breasts and around your chest. These are your ‘bust measurements’. Next, take the tape measure and measure around your frame, just below your breasts. These are your ‘under bust measurements’.


You can take these measurements and put them in any number of bra size calculators that you find online. We like this one


Once you’ve done this, have a look at your ‘true’ size. Does it seem close enough to the size you’re wearing? It’s also important to note that ‘sister sizing’ refers to two bra sizes that have very similar cup volume. The sister size of a 34B is 32C. The cup size of the first sounds smaller but it’s actually very similar to the cup size of the second, because cup sizes are relative to the bands! So don’t worry if your cup size is a little different – try it and see if it’s a better fit for you.


Ok so once you have your true size based on your new measurements, you can also use that for Bra Lab shopping like we’ve shown you above.


If you have any comments or questions don’t hesitate to reach out. We’re bringing more styles soon and hope to find a great fitting bra for all our customers!



 The Bra Lab Team




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