Band size finder
| Underbust (inches) | Underbust (cm) | UK band | EU band |
|---|---|---|---|
| 27–29 | 69–74 | 28 | 60 |
| 29–31 | 74–79 | 30 | 65 |
| 31–33 | 79–84 | 32 | 70 |
| 33–35 | 84–89 | 34 | 75 |
| 35–37 | 89–94 | 36 | 80 |
| 37–39 | 94–99 | 38 | 85 |
| 39–41 | 99–104 | 40 | 90 |
| 41–43 | 104–109 | 42 | 95 |
| 43–45 | 109–114 | 44 | 100 |
| 45–47 | 114–119 | 46 | 105 |
The ranges meet at the odd numbers. If you measure exactly on one, such as 31 or 33 inches, you are between bands, and the section below is for you.
The rule in one line
Measure snugly around your ribcage directly beneath your breasts, and round to the nearest even number. That is all. If you have not measured yet, how to measure your underbust covers tape position and tension.
Older size guides tell you to add four or five inches to this number. That instruction dates from bras made of non-stretch fabric, and with modern elastic it gives a band too loose to support you. The evidence is in why the +4 method is wrong.
If you are between two bands
Bands only come in even numbers, so about half of all people measure between two. Three things help you choose.
How your ribcage feels
Press your fingers into your side just under the bust. If there is a soft layer, a firmer band will settle into it comfortably, so lean towards the smaller band. If you feel rib straight away, a very firm band will press on bone, so lean towards the larger.
Your cup size
A heavier bust needs a firmer anchor. From roughly an F cup upward, the smaller band usually gives noticeably better support. With a small bust there is less to hold up and the larger band is often more comfortable.
The bra
Bands differ in stretch between brands. Try both sizes where you can and use the tests in how tight a bra band should be.
When you switch between the two bands, change the cup letter the opposite way to keep the same cup volume. A 32E and a 34DD hold the same amount. The sister size chart gives the pair for any size.
Band is only half the size
The band number has no cup information in it, and the cup letter depends on which band you choose. Once you know your band, measure your bust and subtract the band from it, or let the calculator do both steps. For how the band, the hooks and the cups work together, see bra band sizes explained.
Frequently asked questions
Is my band size the same as my underbust measurement?
Very nearly. Your band is your underbust measurement in inches, rounded to the nearest even number. A 31¾-inch underbust is a 32 band. Nothing is added.
My underbust is 33 inches. Am I a 32 or a 34?
You are between the two, and either can be right. Try the 32 if you like a firm band or have some softness around the ribs, and the 34 if your ribcage is bony or you dislike a snug fit. Use the sister size so the cup stays the same: 32E and 34DD, for example.
Is band size the same as dress size?
No. Dress size follows your bust, waist and hips. Band size follows only your ribcage directly under the bust. Two people in the same dress size often wear different bands.
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