Bra Size Chart & Calculator

Our handy bra size chart can help you find your size. Just follow the simple steps below.

Calculate Your Bra Size in 4 Easy Steps

Step 1: Measure Under-Bust

Wrap a soft tape measure around your rib cage where your bra band typically sits (see image). Make sure the tape is level and not hiking up or falling back.


Step 2: Measure Bust

Wrap the tape measure around the fullest part of your bust. Make sure it's level and fits snugly.


Step 3: Calculate Band Size

If your under-bust measurement is an even number, add 2 inches to calculate your Band Size. If your under-bust measurement is an odd number, add 3 inches to calculate your Band Size. For example:

You're measuring 35.6 inches, your Band Size is 38

You're measuring 34 inches, your Band Size is 36

See the Find Your Band Size chart below.

Image description

Band Size Chart

Inches: 25-28.5"

Band Size: 30

Inches: 28.5-30.5"

Band Size: 32

Inches: 30.5-32.5"

Band Size: 34

Inches: 32.5-34.5"

Band Size: 36

Inches: 34.5-36.5"

Band Size: 38

Inches: 36.5-38.5"

Band Size: 40

Inches: 38.5-40.5"

Band Size: 42

Inches: 40.5-42.5"

Band Size: 44

Inches: 42.5-44.5"

Band Size: 46

Step 4: Calculate Cup Size

Now that you know your Band Size, subtract that number from your bust measurement. For example:

Your Band Size is 38 and your Bust is 42", the difference is 4", so your Cup Size is D

Your Band Size is 36 and your Bust is 38.5", the difference is 2.5", so your Cup Size is B½

Cup Size Chart

Difference: 0"
Cup Size: AA

Difference: 1"
Cup Size: A

Difference: 2"
Cup Size: B

Difference: 2.5"
Cup Size: B½

Difference: 3"
Cup Size: C

Difference: 3.5"
Cup Size: C½

Difference: 4"
Cup Size: D

Difference: 4.5"
Cup Size: D½

Difference: 5"
Cup Size: E

Difference: 5.5"
Cup Size: E½

Difference: 6"
Cup Size: F

Difference: 7"
Cup Size: G

Difference: 8"
Cup Size: H

How to Use the Bra Size Chart

ThirdLove offers over 60 bra sizes from 32 to 44 band and bra cup sizes from AA to H cup, including our exclusive half cup sizes. Using your current bra size as a starting point, you can refer to the bra cup size chart above to refine your fit.

When using the chart to find your bra size, keep in mind:

  • The band size increases as you move from left to right. Move left or right within the row if your band doesn't fit.
  • The cup size increases as you move from top to bottom on the chart. Move up or down the columns if your cups don't fit. In between cup sizes? Go up or down a half-cup!
  • Bra sizes that share a row are sister sizes, meaning they share the same cup volume (though they have different cup letters). For example, at a glance they’re all just different bra sizes. However, the row with bra sizes 36C, 38B, and 40A have something in common: they all have the same cup volume but have different band sizes. The same goes for the row with bra sizes 38H, 40G, 42F, 44E, 46D, and 48C.


There are two primary components of bra sizes: the bra cup sizes and the band sizes. They’re also critical indicators of a proper fit.


Think of bra cups like a glass of water: it only holds a certain volume. You don’t want a cup that’s too big (puckering) or a cup that’s too small (overflowing all over.) The ideal cup lays flush against the breast comfortably without cup spillage or gaping. ThirdLove created half cup bra cup sizes specifically to help every bra wearer find the right size for their body.

The center of the bra, where the bra cups connect, is called the gore, or sometimes the bridge of the bra. If your cups fit properly, the gore should lay flush against your sternum. It shouldn’t hover over the chest (a sign of overflowing cups!) or dig in.

If the bra has an underwire, it should lay comfortably under the breast tissue, providing support without digging into the sides of the breast tissue or into the underarm area. Placement anywhere besides cupping the underside of the breast is a clear sign of improper fit: the underwire shouldn't lay on your breast tissue or below your rib cage.


The bra band should feel snug yet comfortable on the loosest set of hooks. This allows you to move to the inner hooks to tighten the bra as it stretches with regular wear. The bra band should be parallel to the floor and should not ride up.


The straps are tightened so that they fit snugly and comfortably on your shoulders. They shouldn’t slip off or dig into your shoulders. The straps should also be positioned on the center of each of your shoulders — not too far on the edge where it can slip off and not too close to the neck where it can feel uncomfortable.


“But I’ve had this bra since high school, and it still fits.”

“This new one in the same size is too small, so it has to be the bra.”

Sad but true, even The Perfect Bra will eventually meet its end. If the bra has been a staple (a.k.a. in heavy rotation) for over a year, check for wear and tear. For example, if materials have stretched out, there’s a good chance neither you nor the bra are the label size anymore! Our Fitting Room Quiz can check your size in less than two minutes.

“Oh, that’s just my armpit fat.”

Bodies come in many beautiful shapes and sizes. For some, choosing a smoothing bra style can give them the visual silhouette they’re looking for. However, it can be possible that the “squish” that’s being perceived around the front of the armpit is actually breast tissue that didn’t fit inside the cup, and instead, it’s escaping out of the sides. If you’re on the middle to smallest hook, try going down a band size and up a cup size. Try wearing this sister size with a greater cup depth on the largest hook.

“My bra straps dig in, and it hurts!”

Bra strap fact: straps are really there to do only about 10% of the work. The bra cup and bra band should do most of the support work. If straps leave painful marks on your body, they’re working too hard! Check your cup and band fit, and consider trying a band size down and a cup size up (a sister size) for a deeper cup and firmer band.

“My band rides up in the back.”

If it can move, it’s too big! If your bra is fairly new and the cups fit well, try going up a cup size and down a band size for an equivalent volume (sister size.)

Or sometimes, when you’ve done your job for a little too long, you get a little too relaxed when doing it. If your go-to everyday bra has celebrated a birthday, it could be time for a replacement. Time to check for wear and, most importantly, check your bra fit!

“I can only wear it on the smallest hook. I go through bras so fast!”

Where you hook your bra can help you troubleshoot fit using the bra size chart above. Let’s say a size 36D bra wearer has three sets of hooks on the back of their bra. The ones that make it largest are like saying “37,” the center “36,” and the smallest “35.”

If they’re wearing it new on the smallest hook, there’s nowhere to go when it stretches with wear, shortening the life of the bra. It’s possible that moving to their sister size of a smaller band and larger cup, where they can likely start on the largest hook, could be a better overall fit.

“It’s hard to find my cup size so I just buy the DD, and sometimes, I wear two bras.”

Whether it’s every day or working out, if you have to wear two bras, neither is doing its job!

Discomfort and short bra longevity are signs you’re settling for an improper fit. We offer cups past D—to H—and created Precise Sizing™ to combat the issues smaller bands with full cups face when looking for a wireless bra for large busts. If you’re near a retail location, one of our Fit Stylists can work with you in person.


There are no bad boobs, only bad bras. Just like shoes or jeans, only some people will fit comfortably into the same style! Knowing your breast shape can help you select the right style for it. Better fit = more comfortable, so what’s not to love? Let’s get into it.


It’s common to have asymmetric breasts in combination with any of the other shapes. 40 percent of women have breasts that differ in size, ranging from a slight asymmetry to an entire cup size difference.

FOR YOUR SHAPE: Try bras with removable inserts if you’d like to even out your natural shape. Our curated collection of bras for asymmetric breasts will help you balance your shape.


This shape features wider, more muscular breasts with less tissue. Cup gaping tends to be a common issue for Athletic shapes due to the lack of volume up top.

FOR YOUR SHAPE: Just-right coverage is key for a smooth look, and our bras for athletic breasts are a great place to start.


Slimmer at the top and fuller at the bottom, this shape typically characterizes women with larger cup sizes. Bell shapes may commonly experience overflow with minimal coverage styles like balconette or demi.

FOR YOUR SHAPE: Bras with full coverage are a great choice. Our collection of bras for bell shaped breasts features styles with memory foam straps that provide support and never dig in in.


With lax tissue and nipples that point downwards, folks with this shape tend to have longer breasts that hang.

FOR YOUR SHAPE: Try styles with a slightly shorter cup for more fullness at the top such as those in our collection of bras for relaxed breasts.


Like the name implies, East West shape is characterized by wide-set breasts that gravitate away from the chest center. The nipples tend to point outwards in opposite directions. Those with this shape may find it is more difficult to achieve cleavage with certain tops.

FOR YOUR SHAPE: styles that are full coverage and help bring your breasts up and together are great when shopping for bras for East West breasts.


Equally full at the top and bottom, often round shapes find they only need a little coverage and support, making many padded bras unnecessary.

FOR YOUR SHAPE: Most styles will work well for your shape, but explore wireless bras for days when you only want light support and balconette styles for when you want an ultra-flattering fit. They’re all in our curated collection of bras for round breasts.


Similar to East West shapes, side set shapes tend to have a wide center gap but fuller-shaped breasts with nipples that face more forward.

FOR YOUR SHAPE: Explore bras made to naturally lift and draw your breasts closer together, such as those in our collection of bras for side set breasts.


If you have thin breasts with nipples that point downwards, you may have this shape. Slender shapes are typically smaller in size, with breasts that are slightly longer than they are wide.

FOR YOUR SHAPE: Explore bras made to give you a natural, flattering lift in our collection of bras for slender breasts.


Like bell shapes except rounder, while teardrop shapes are round, they are slightly less full at the top. If you have this shape, you may experience cup gaping with full-coverage bras.

FOR YOUR SHAPE: A wide variety of styles will suit your shape, but for more fullness up top, try a balconette style. Our collection of bras for teardrop breasts features a wide range of silhouettes that will enhance your shape.

Understanding Breast Shape

Asymmetric Breasts
Athletic Breasts
Bell Shaped Breasts
Relaxed Breasts
East West Breasts
Round Breasts
Side Set Breasts
Slender Breasts
Round Breasts
Tear Drop Breasts
Bra Sizing FAQs

If your straps fall down, your cup size may be too big.

Explanation: They’re being pulled away from your body because the bra cup cannot lay flush.

If your straps dig in, your band may be too loose.

Explanation: Are your straps cranked super tight? Your band and cup aren’t holding on (and holding up), so the straps are carrying too much weight.

If you fix it often/your band moves, your band may be too loose.

Explanation: A band that has room to move is too large. That too-large band may be overcompensating for a too-small cup.

If there’s puckering in the cups, your cups are too large.

Explanation: If the cup cannot sit flush against the body, it will buckle to try to help fill the space. A lesser coverage style may work if it is very minor. Otherwise, you may need to size down.

If the center gore stands away from your body, your cups are too small.

Explanation: the cups aren’t overflowing out of the sides or over the top, so it may appear that the bra fits. However, if the center where the cups meet does not touch the body, that means the breast tissue is pushing away.

If there’s poking, your cup size may be incorrect.

Explanation: one possibility is the wire is unable to properly cup the underside the breast and is poking because it’s too small. On the other hand, a too-large copy gives the wire the ability to move, which can also cause poking.