Most women wear the wrong size bra. We know that. And yet, so many of us are still wearing the wrong bra size! Why is that? I’ll tell you in a little bit.

First, I want to make something clear:

If you’re feeling any less than 100% comfortable in the bra you’re wearing right now, it’s the wrong size for you. And you deserve a bra that fits you perfectly. If you’ve never measured yourself properly and without a bra on, I strongly suggest you try it out for yourself.

Most women think they’re wearing the correct bra size until they try on a bra that fits them like pure heaven.

There are a few reasons why so many women are still wearing the wrong bra size.

#1) Our real bra size is not available at most stores.

Popular bra manufacturers — think Victoria’s Secret, Aerie, and most mainstream stores we all shop at — only carry limited sizes. Typically their band sizes go from 32 to 38 and their cup sizes from A to DD.

But did you know that 7 out of 10 women are outside of this range when measured correctly? Most of these women settle for a sister size with a band that’s too large. In other words, they settle for a poor fit.

#2) Bra fitters aren’t always reliable.

Professional bra-fitters in stores don’t know how to measure you properly — generally speaking. Their training is based on innacurate techniques like the overbust measurement (measuing you above your bust) or the “plus 4 rule” (they add 4 inches to your measurement, which you should never do!).

Some fitters like to eye-ball measurements, which yields to horrible results no matter their experience.

Others work on commission and will gladly point you to the wrong size only to make a sale. I apologize to all the honest and competent bra fitters out there, but it’s unfortunately a reality in some stores.

#3) We underestimate our cup size.

“Me, a DD cup?! No way!!!”

Yes way, sister. Many women underestimate their cup size and refuse to believe that they’re really a DD or bigger, based on the misconception that a bigger cup means a bigger and bigger boobs.

In reality, you can wear a DD cup without having (pardon my French) giant knockers.

You see, cup size is totally dependent on band size. Please read my article on sister sizes if you’re not familiar with this, but basically: a 28DD and  a 34B have the exact same cup volume.

#4) We think our oversized bras fit.

Women overestimate their band size because a band that’s too large still feels like it “fits”.

This is very important: Most support from your bra should be from the band, and the band should be tight on your torso. The straps are only there to hold everything in place, not to support your bust!

A size 38″ band might “fit you”, but if your straps are supporting your bust, it’s too big! If your band is too big, size down in the band and size up in the cup (remember sister sizes!).

The Real Way To Measure Yourself

The method we use is a mix of proper measurements and common sense. Bra-fitting is not an exact science, but if you take the measurements mentioned below and add your personal experience and common sense to them, you’re going to figure out your correct bra size in no time.

What You’ll Need

Don’t have a flexible tape measure? Either use a rigid one or a ruler paired with any type of string, or just buy one here.

How To Determine Your Band Size


Step 1. Measure your underbust

Measure around your ribcage, right under your bust, keeping the tape snug.

The tape should be neither loose not tight, just snug. Make sure the measuring tape is straight! I like looking in the mirror to make sure it forms a straight line all around my body.

Also make sure that you don’t measure around any breast tissue; you want to measure your underbust, where the band should sit on your torso.

Step 2. Round up to the next nearest even number

..And this number is your real band size.

Do NOT add anything more than that.

Do NOT add 4 inches.

Do NOT pass go.

Compare this result with the band size of a bra you already own. If you can fit more than 2 fingers under the band, it’s too big.

Generally speaking, this will be your real band size. There are, however, some exceptions.

Adapt this measurement to your needs and use common sense. It’s an art, not an exact science. You’ll see what I mean in the examples.

  • Example 1: Your underbust measurement is 27.5″ and you currently wear a size 30″ band. The 30″ band fits you very tightly. Rather than rounding up to 28″, go another size up to a 30″ band.
  • Example 2: Your underbust measurement is 36.5″ and you currently wear a size 36″ band. The 36″ band does not fit tightly around your ribcage, and you can squeeze 3 fingers or more under your band. Rather than go up to a size 38″ band, size down to a 34″ band.

How To Determine Your Cup Size


Measure around your naked breasts, at nipple level. Keep the tape loose, almost loose enough for it to fall down. Now substract your underbust measurement from your band measurement.

US Vs. UK Sizing Differences

To determine your cup size, look at the table below. You’ll notice that your result will be different based on the country. Whether you’ll need your US, UK, or European size depends on the country of origin of your bra manufacturer.

The cup sizes remain the same up to a DD cup, after which the 2 size charts differ slightly. The UK system has double letters (DD, FF, GG) in-between single letters (D, E, F, G) although it skips a double E. The US system is more straightforward and essentially follows the alphabet.

Many popular manufacturers are based in the UK, which means they use UK Sizing. These manufacturers are Freya, Panache, Gossard, Curvy Kate, Fantasie, and Bravissimo.

Some popular manufacturers that use US Sizing include Wacoal, Victoria’s Secret, Cacique, Goddess, Maidenform, and Le Mystere.

I suggest you takenote of both your US and your UK size (and of course, don’t forget to specify which is which).

Band Minus Bust Difference US Cup Size UK Cup Size Euro Cup Size
Less Than 1″ AA AA AA
1″ A A A
2″ B B B
3″ C C C
4″ D D D
5″ DD or E DD E
6″ DDD or F E F
7″ G F G
8″ H FF H
9″ I G I
10″ J GG J
11″ K H K
12″ L HH L
13″ M J M
14″ N JJ M

Example: Let’s say your bust measures 38″, your underbust measures 29.5″, and your band size is 32″ . The difference is 6″, which corresponds to an F cup. Your size would therefore be a a 32F.

Surprised At Your Result?

Many women are. But I guarantee you that if you try on a bra in the size you just measured, you’ll be so glad you did.

Once you determined your correct size, you can move on to the Guide To Breast Shapes in order to determine your shape, and learn what works best to complement it.

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  • My band size is 26.5″, and my bust size 29″. What bra size am I? I’m a bit confused with the example ” your bust measures 38″, your underbust measures 29.5″, and your band size is 32″ . The difference is 6″, which corresponds to an F cup. Your size would therefore be a a 32F.” why would a 29.5” under bust translate to a 32″ band size, if “..And this number is your real band size.

    Do NOT add anything more than that.

    Do NOT add 4 inches.”

    1. Hey Maya! In your case with a measurement of 26.5″ you’re typically looking at a 28″ band. I would try both a 28A and 28B.

      I always suggest using the bras you already own to determine your ideal band size, which is what my example is based on. Someone with a band measurement of 29.5″ can either go up to a 30″ or 32″ depending on their body type or fat tissue.

  • I’m still so confused…..
    I barely fill out my 36C bra
    I’ll admit I have very teardrop shaped breasts and all my volume is at the bottom and the top of my breasts are virtually flat.
    Now I went to 4 different lingerie stores, all suggesting I’m a 36DD! It couldn’t be right.
    So I did these measurements, and yeah….even you’re measurement I still got a 36 under bust that fit perfectly (a 38 was far too loose, and I couldn’t get two fingers in with a 34, 36 worked perfectly)
    And at the fullest part I sure got 41 (40 if I pull a little tighter, 39 was impossibly tight)

    So how come I have trouble filling out my C cups if I’m a DD.
    (I tried a 36B too once and that was absolute hell)
    It makes no sense whatsoever

    1. Hey Nicole! First of all, did you have a bra on when measuring yourself? Which bra(s) have you tried in a 36C? You might have shallow breasts that are also full on bottom, and remember that not all bras work with all breast shapes. If you do have shallow breasts, there’s going to be a gap at the “front” of your cups. For full on bottom breasts, the gap will be at the top. My suggestion is to try different bras! This one by b. tempd might have a shape that works with you.

  • So according to this method I would be a 38L. I have never seen this bra size before in any store. I have been looking online and it seems to be very rare there too. Where would you suggest looking?

  • I’m sort of confused! My band size is 33 and when I did my bust I got 38. So that means Im a 33DD? Please help 🙁

  • Can i purchase online and will you ship to Mauritius and at what cost. Do not want to pay 3 times the bra cost on shipping

  • I am still unsure with the examples. My band measurement is a little over 28” and my cup measures 36”. Would my size be 28 H or am I wrong?

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