Why did we develop sizing technology?

Have you ever wondered why it’s so hard to find a bra that fits? So did we! After meeting, measuring, and practically interrogating thousands of women we realized that each of you has a bra story, and it rarely has a happy ending. From pinching wires & size confusion to cold dressing rooms & handsy saleswomen, the message was clear: we deserve better!

You'll see that our band and cup sizes look different from the industry. We've developed more sizes to give you the best possible fit based on your real measurements.

“My TL size is 31B½ but I usually wear a 34B. Why?”


Did you know that a 34B industry size does not mean you’re 34” around? It actually means you’re between 30”-31”. Confusing, right? We thought so too. That’s why your ThirdLove band size is your actual body measurement. For example, an industry 34B equals a TL 31B. Goodbye 34, hello 31 ;)

Cup Size

A, B, C, D.. We’re all familiar with these letters but what about all the ladies that fall in between these cup sizes? ThirdLove developed unique ½ cups sizes to give you a much closer fit. For example, if you see B½, you’re getting a cup between a standard B & C, because our technology recognized that you needed one of our special ½ cup sizes.

What about crossgrading?

Crossgrading, otherwise known as sister sizing can be so confusing. And who suffers in the end? You do. Well not anymore, get ready to have your mind blown. Did you know that 36A, 34B, and 32C ALL have the exact same sized cup? That’s right, they are all a B cup. 32C just means you’re a B cup with a smaller band and 36A means you’re a B cup with a bigger band.

At ThirdLove, if you’re a B cup, you’re a B cup and that’s that! 29B, 31B, 33B are all B cups with different sized bands.

Size yourself with our app

Measure yourself in minutes with your smartphone & our exclusive technology - no measuring tapes, dressing rooms, or a lingerie salesperson required!

Send the download link to your phone:

We’ll let you know when we launch!