Bra Size Calculator & Sports Bra Sizing (2024)

Bra Sizing FAQs

How do I calculate my bra size?

Calculating your bra size is easy. Before you take another online quiz or try to find your size from reading a chart, we'll teach you how to get your measurement and your bra size right. All you need is tape measure and a notepad or notes app to write down your measurements. To get the most accurate measurement possible, make sure you're wearing a non-padded bra. A padded bra adds volume to your bust shape that isn't naturally there, so go for a bralette with a wire. The wire will give just enough support to keep your breasts leveled while you measure.

Let's start with your bra band size. Grab your tape measure, and wrap it around the top of your ribcage, right underneath the breasts. Make sure the tape measure is snug around the torso. If the number you land on is an even number, add 4 inches to the measurement. If it's odd, add 5. Do a quick little addition, and boom, you've got your band size — don't forget this number! Double-check your bra band size is right by measuring around the top of your bust, right below your underarms.

Now let's find your cup size. Wrap the tape measure evenly around the fullest part of your bust. Try to keep the tape measure as leveled as possible. Write down the number you land on.

Your bra size is your band size subtracted by the cup size you just measured. So, let's say you measured 36 inches for your bust, and 34 inches for your band. That's 36 - 34 = 2 inches of difference, making you a 34B. One inch of difference would make you a 34A, three inches a 34C, and four inches 34D. Don't feel like doing the math? Add your measurements to our bra size calculator to get your bra size right.

Is DDD the same as F?
How big is a cup D breast?
What is the bra +4 method? Why do you add 4 inches to your band size?
Is it better to go up a cup size or band size?
Is it better to size up or down in bras?
How do you tell if your cup size is too big or small?
Why does my bra get tighter as the day goes on?
What is the difference between DD and DDD?
Why does my bra ride up in front when I lift my arms?
How tight should a bra be?
Why do my bra straps keep slipping off my shoulders?
Why does cup size increase with band size?
What happens when you go up a band size?

Is DDD the same as F?

The short answer: yes! Here in the US, DDD is the same as F. But, if you were bra shopping in the UK, for example, DDD/F would be E. Some US-based brands don't always get this distinction right, and bra size charts aren't always consistent. But at Title Nine, we consider DDD and F to be the same.

How big is a cup D breast?

If you're measuring your bra size with a tape measure, a D cup is going to come out to 4 inches of difference from your band size. A D cup is not the same as DD cup or DDD cup. If you're a D cup and want a comfortable bra fit, easy support, and ideal coverage, you've got tons of options to choose from, from minimizer bras, to full coverage bras, to everyday bras that fit and feel like your favorite sports bra.

What is the bra +4 method? Why do you add 4 inches to your band size?

You'll only need to add 4 inches to your band size if you're measuring with a tape measure and it lands on an even number when wrapped around your ribcage.

Is it better to go up a cup size or band size?

That all depends on the bra fit you're going for. Obviously, you want to be comfortable, but sometimes we need to do a little band and cup size hacking to get the best fit possible. Your cup size is influenced by your band measurement, so if the band changes, so does the cup. That said, it's not necessarily better to go up a cup size over band size, and vice versa. It's all relative—when one changes, so does the other. If you're happy with your cup fit but want a bit of a looser fit around the band, size up on the band. If your cup fit is too snug but the band feels just right, go up one cup size.

Is it better to size up or down in bras?

Whether it's a sports bra or an everyday bra, sizing up or down isn't the move. The key is to get your size just right so you get the support you need without sacrificing comfort. There are some exceptions, though. If you're in the middle of weight loss, weight gain, pregnancy, or post-partum, and you're preparing to fit into a new bra size, then sizing down or up would be OK in this case. We suggest waiting on this, though—you don't want your breasts to be squished or floating around in your bra.

How do you tell if your cup size is too big or small?

Sometimes you don't need to look at a chart to know your bra isn't fitting right. There are some easy tell-tale signs of a poor-fitting bra.

Your cup size is too big if...

There's extra space between your breast and the cup (AKA a cup gap)
You don't feel supported by your bra
You're constantly readjusting your bra
You've tightened the adjustable straps to compensate for the cup gaps

Your cup size is too small if...

Your breasts are spilling out of the cups
You've got side boob—another sign the cup isn't covering the whole breast
The underwire is poking you
You have red marks on your breasts after taking your bra off
Your breasts are squished together at the center of your chest

Why does my bra get tighter as the day goes on?

It's totally normal for your bra to feel tighter by the end of the day. It all comes down to the natural fluctuations and hormonal changes women go through every single day. Our breasts, and therefore our bust size, can either shrink or swell up morning to night for a number of reasons: water intake, exercise, breastfeeding, and more.

What is the difference between DD and DDD?

DD and DDD cups are two completely different cup sizes. DD will have 5 inches of difference from your band size, and DDD will have 6 inches of difference. DDD is also often recognized as an F cup.

Why does my bra ride up in front when I lift my arms?

If your bra rides up in the front, this is another sign you're wearing the wrong size. It's likely that the band is too loose, and you need to size down to a more snug fit that keeps your bra in place.

How tight should a bra be?

A bra should fit not too tight, not too loose, but just right. A nice and snug fit on the band and comfortable fit on the cups is a pretty good tell that you've got your fit just right.

Why do my bra straps keep slipping off my shoulders?

If you find yourself constantly pulling your straps up and back in place, it might be time to replace your bra. It could also be a sign that you're wearing the wrong size bra altogether. If the adjustable straps can't be tightened anymore and still slip off, the fabric has reached its limit and won't stay in place.

Why does cup size increase with band size?

Cup size will always change with the band size. This is because the measurement of your band influences your cup size.

What happens when you go up a band size?

If you go up a band size, you'll likely have to go down a cup size to compensate the difference. To be totally sure, though, measure yourself again either with a tape measure or fit expert.