Measuring your bra size: getting your band and cup size right

Your bra size is made up of two numbers: your band size, measured snug under your bust, and your bust size, measured around the fullest part of your chest. The difference between those two numbers tells you your cup size: the bigger the gap, the bigger the cup. Below you'll find exactly how to measure both numbers, how to compare them, and a quick self-check to make sure the result actually holds up on your body.

Step 1: measure your band size, the foundation of every bra size

Measure your band size snug under your bust, right where a bra band normally sits. Do this without a bra on, with the tape measure wrapped straight around your ribcage, horizontal, not angled up or down. Pull the tape until it fits closely but doesn't dig into your skin.

A lot of women measure too loosely here. That makes sense: a loose tape feels more comfortable than your actual band size. But a band that fits a bit snugger actually gives you more support, since about 80% of a bra's support comes from the band, not the straps.

Quick check: breathe out normally and see if you can just barely fit two fingers between the tape and your skin. If that's easy, or if you could slide your whole hand under there, you're measuring too loose and need to pull the tape tighter.

Step 2: measure your bust size, that's how you find your cup size

For your bust size, measure around the fullest part of your chest, usually right at nipple level. Same rule here: straight around your body, measured horizontally, without pulling the tape tight. This number can sit looser than your band measurement, since you're measuring volume here, not pressure.

It's best to do this without a bra, or with a thin bra that has no padding. A push-up or a heavily padded bra will throw off the result, because then you're measuring the shape of the cup instead of your own body.

Quick check: stand in front of a mirror with the tape around your chest. If the tape dips lower on your back than in front, you're measuring at an angle. Start over and make sure the tape stays level all the way around.

Step 3: the difference between the two numbers determines your cup

Subtract your band size from your bust size. The difference in inches translates to a cup letter. Here's a rule of thumb you'll find in almost every bra size chart:

• 1 inch difference: cup A
• 2 inch difference: cup B
• 3 inch difference: cup C
• 4 inch difference: cup D
• 5 inch difference: cup DD
• 6 inch difference: cup DDD
• 7 inch difference: cup G
• 8 inch difference: cup H

Say your band measures 36 inches and your bust measures 42 inches. That's a 6 inch difference, which lands you somewhere around a DD to DDD on this scale. Keep in mind: this is your raw bra size in inches, not automatically your size label. At Monavida we work with sizes from S through 3XL, which are converted behind the scenes from exactly these kinds of numbers. Always check the size chart on the specific style you want to order, that way you know your numbers line up with the right S, M, L or XL.

Quick check: does your calculated size actually hold up?

A calculation is a starting point, not a guarantee. Body shape, breast tissue and the cut of the bra all play a role. So always double check the result in the mirror or with your hands.

• Push a finger under the band at your back. If you can slide more than two fingers under there, the band is too loose.
• Look at the top of the cup. If there's a gap between your breast and the fabric wider than a finger, the cup is too big.
• If your breast spills out over or beside the cup, the cup is too small and you need to go up a cup size, possibly down a band size to match.
• If the band rides up toward your shoulder blades in back, it's too loose and isn't doing its job.

Plenty of customers who email our customer service team give us exactly these two numbers: band and bust measurement. That lets us tell right away whether a size is right, without you having to ship back a whole bra just to find out. You can read exactly how that works in How to share your bra size by chat or email.

Why two women with the same numbers can still wear different sizes

Of nearly 2,900 women we surveyed for Monavida, over 8% name the wrong size or cup as their biggest complaint about their bra. That's striking, because most women do measure themselves. The problem usually isn't the measuring itself, it's everything around it.

Your body changes throughout the day, with your cycle, with weight shifts. A band that fits perfectly in the morning can feel tight by evening. On top of that, elastic stretches out a little after a few washes, so a bra you've had for a year can feel like a different size than when you bought it. And not every brand cuts its patterns the same way: a 36C in one brand can run more like a 34D in another. You can read why that happens in Why does my bra size differ between styles from the same brand?

I don't care so much about the number, I just want it to finally feel good and not curl up under my breasts

That line gets right to the point. It's not the number on the tag that matters, it's whether the band stays put and doesn't ride up when you sit or bend over. A well-measured size is the foundation, but how it feels on your body is the real test.

Stuck between two sizes? Here's what to do

If you land between two sizes, say a 36D and a 38C, the rule of thumb is: size down in the band, size up in the cup. Try the smaller band with the larger cup first. A snugger band holds its shape better, and since band and cup work together, the cup often adjusts a notch on its own.

With the Daily Essential Bra, a 3 inch wide band means your breasts' weight rests on your ribs instead of your shoulders. The memory foam cups then shape themselves to your body, so small differences between two sizes stand out less than they would with a stiff cup that has no memory foam. The size chart for this style runs from cup B to cup H, with band sizes from 32 to 48, across twelve sizes from S through 3XL+.

Still torn between two sizes? Order a bra with an adjustable closure and straps, so you can fine-tune the fit yourself by an inch or so. And if the size still isn't quite right after you try it on, you don't have to send everything back right away. Find out what to do instead in Ordered the wrong bra size? Here's what to do.