12/2/2025 Bras Size and fit

Bra Size Guide

How a Properly Sized Bra Should Fit You

A well-fitting bra has a properly sized band that doesn’t ride up in the back. A snug band in the right size reduces strain on your shoulders. Cups in the right size fully contain your breasts without spilling over the top or sides. Above all, a well-fitting bra feels comfortable. It’s also the right style for you if it stays in place without needing adjustments throughout the day—so comfortable that you hardly notice it’s there.

How to Measure Your Bra Size

Start by measuring around your ribcage, directly under your bust. Pull the measuring tape as tight as possible, since the bra stretches but the tape does not.
Measure around your bust. For the best results, wear a bra and measure around the fullest part of your bust.
Determine your band size. Find your underbust measurement in the chart below. For example, if your measurement is 87 cm, your bra band size is 85.
Determine your cup size. The difference between the two measurements determines your cup letter. For example, if your underbust measurement is 87 cm and your bust measurement is 108 cm, the difference is 21 cm (108 cm - 87 cm = 21 cm). Find the cup letter corresponding to the difference in the chart below.

Underbust measurement	EU size	UK size	Clothing size	EU clothing size	UK clothing size
58-62	60	28	XXXS	32	4
63-67	65	30	XXS	34	6
68-72	70	32	XS	36	8
73-77	75	34	S	38	10
78-82	80	36	M	40	12
83-87	85	38	L	42	14
88-92	90	40	XL	44	16
93-97	95	42	XXL	46	18
98-102	100	44	3XL	48	20
103-107	105	46	4XL	50	22
108-112	110	48	5XL	52	24
113-117	115	50		54	26
118-122	120	52		56	28

Difference	EU Cup Size	UK Cup Size
11	AA	AA
13	A	A
15	B	B
17	C	C
19	D	D
21	E	DD
23	F	E
25	G	F
27	H	FF
29	I	G
31	J	GG
33	K	H
35	L	HH
37	M	J
39	N	JJ
41	O	K

Fitting video

What is a sister size?

You may need a sister size if the cups of the bra you’re trying on fit well, but the band feels too tight or too loose. A sister size has the same cup volume but a different band size. For example, the sister sizes for 85E are 80F and 90D. When you go down a band size, you go up a cup letter, and when you go up a band size, you go down a cup letter.

Bra sister sizes – see examples

The Most Common Reasons for a Poor Bra Fit

Bra band is too large

Your bra band is too large if the back of the bra rides up. If the band is too large, the underwires will lift away from your body when you raise your arms. In this case, choose a smaller band size. A band that is too large places too much weight on your shoulders, causing unnecessary strain. It's best to fasten your bra on the first, or loosest, set of hooks. This leaves room to tighten it later if needed.

Bra cups are too large

Your bra cups are too large if your breasts don't fill them and there is empty space inside. Cups that are too large don't provide enough support. The fabric may wrinkle, and padded cups may gap away from your breasts. The underwires will also be out of position: they may lift away at the center and poke uncomfortably into your underarms. The underwires should sit against your skin all the way around and follow the shape of your breasts, with all breast tissue contained inside the cups. In this case, go down a cup size.

Bra cups are too small

Your bra cups are too small if your breasts don't fit fully inside and spill over the tops or sides. When the cups are too small, the underwires press on breast tissue instead of sitting properly underneath and between your breasts. In this case, go up a cup size.

Why Do Bra Straps Slip? Causes and Solutions Breast support and choosing the right bra style

How to Get It Right: 7 Things to Remember

Choose a bra based on how you plan to use it.
When trying on a bra, make sure it is fastened on the outermost, loosest hooks.
Adjust the straps to a comfortable length. Avoid tightening them too much, as most of the bra’s support comes from the band.
The band should sit level all the way around and not ride up in the back. It should fit snugly and comfortably to provide the best support.
Make sure the underwires sit firmly against your body beneath your breasts.
Make sure the cups sit against your skin without any spillage or gaps.
Try the bra on with a shirt, too. This will show you the shape it creates and help you confirm that the cups are the right size.

Swimwear Sizing

A good swimsuit fits well and looks beautiful, but above all, it should be the right size. Our selection includes one-piece swimsuits and two-piece swimwear, including bikinis and tankinis. Our high-quality swimsuits are suitable for both the pool and the beach.
It's important that your swimsuit is the right size. When trying one on, it should feel comfortably snug, as the material may loosen slightly when wet. Our swimsuits generally hold their shape well, though this depends on how often you wear them.

Choose your swimsuit size based on your clothing size. Consider your torso length, too: if you're tall, choose a larger size. The exception is PrimaDonna Swim one-piece swimsuits, which use bra sizing, such as 85C. All our swimsuits also have cup sizes to ensure a good fit around the bust and provide the best possible support. Your swimsuit cup size doesn't necessarily need to match your bra cup size, as a smaller cup size is often sufficient in swimwear.
For bikinis and tankinis, you can generally choose your usual bra size. Bikini bottoms should fit comfortably snug, as the material loosens slightly when wet. If you're between sizes, choose the smaller one.

Choosing Bikinis and Swimsuits for a Larger Bust Shaping swimsuit – support and fit