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.
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.