Your guide to a well-fitting bra

Breasts are made up of tissue that doesn’t contain any muscle, so wearing a bra helps to support the breasts and give a defined shape. A well-fitting bra can help you feel more comfortable and confident.

Just as breasts come in all sizes, so do bras, with band sizes ranging from 28 to 56 inches and cup sizes ranging from AA to L.

The band refers to how the bra fits around your back and the cups are the part of the bra that supports your breasts.

Studies show most people are wearing the wrong size bra without realising it.

Measuring your bra size: your options 

Department stores and specialist bra shops usually have trained fitters who can help you find a bra that fits you properly. You can ask to be measured – you may need to make an appointment in advance.

You can also measure yourself at home using a tape measure. Make sure you’re not wearing a padded bra as you do this.

Step 1

Wrap a soft fabric tape measure around your body just beneath your breasts, pull it tight and record the measurement in inches. Add 4 inches (or 5 if you get an odd number) to this number. This is your band size.

For example, if you measure 30 inches you would then add 4 and your band size would be 34. If you measure 31 inches, you would add 5 and your band size would be 36.

Step 2

Loosely measure around your body with the tape measure across the fullest part of your breasts.

Step 3

Now subtract the smaller number (band size) from the larger number to work out the difference. The table below shows what your cup size is based on the number you get.

For example, if the smaller number is 34 inches and the larger number is 36 inches, you would subtract 34 from 36 to get 2. Your cup size would be C and your bra size would be 34C.

The size measured should only be used as a guide as bra sizes can vary depending on style and brand. This is because some bra fitters and manufacturers may measure your band size and cup size differently. They may not add the 4 or 5 inches and they may measure your cup size by sight.

It’s important to try on a bra before you buy it. You may need to try on several different bras and sizes before you find one that fits well. 

If you can’t try on the bra in a shop or it comes by post, check that you can return it if it doesn’t fit.

The best way to put on a bra is to put your arms through the shoulder straps then lean slightly forward so your breasts fall naturally into the cups. If you can’t lean forward, you can scoop your breasts into the cups.

Adjust the band so it lies flat against your chest underneath your breasts. Fasten the bra on the set of hooks that feels most comfortable for you.

You might find it easier to put the bra on back to front, so the hooks are at the front. You can then fasten it and twist it around so the hooks are at the back, before putting your arms through the shoulder straps.

Make sure the band is level all the way around. Adjust the shoulder straps so that they are not digging into your shoulders (too tight) or slipping off your shoulders (too loose). You can place 2 fingers under the strap at the shoulder to ensure it’s comfortable.

It can help to check how your bra feels and what it looks like in a mirror.

A well-fitting bra should:

1. Feel comfortable and have a level band at the front and back
2. Sit flat against your chest at the centre
3. Not feel too loose or tight, with your breasts filling the cups and the band fitting close to your body
4. Contain your whole breasts without them bulging out
5. Have comfortable shoulder straps that don’t dig in or slip down
6. Have underwires that lie flat against your skin following the natural crease of the breast, without digging into any breast tissue, particularly under the arm
7. Stay in place when you lift your arms above your head

If your bra is too tight or the cups are bulging, try a larger bra size. Most people have 1 breast bigger than the other so make sure the cup fits your larger breast. You may need to go down a band size and up a cup size to find the best fit for you.

If the band feels too loose or the cups are gaping, you should try a smaller bra size. You may need to go down a cup size but up a band size.

The images below show how your bra should fit.

You may also want to check how the bra looks under your clothes – a light-coloured T-shirt or top can help show where it doesn’t fit correctly. Your bra should look like it fits well and feel supportive and comfortable – if it doesn’t then try another.

Wired bras

Some bras have wires to give extra support and structure. Whether you wear a wired or wireless bra is entirely up to you. If you wear a wired bra, it’s important that the wires don’t dig into the breast tissue.

Unwired bras and bralettes 

Non-wired bras such as bralettes can be very comfortable to wear and still offer some support.

Multiway or strapless bras

If you need to buy a multiway or strapless bra to wear with a specific outfit, such as a halter neck or strapless top, take the clothes with you so you can try them on together.

Sports bras

If your breasts are unsupported or move around a lot during physical activity, you might find it helpful to wear a sports bra. Sports bras are designed to increase comfort while minimising movement, and give your breasts extra support.

Minimiser bras

If you have larger breasts, you may like to try a minimiser bra. These have larger cups and cover more of your breast. They distribute your breast tissue across a wider area to make them look smaller and can make it easier to wear certain clothes over the top.

Maternity bras

If you’re pregnant, think about buying a well-supporting bra or a maternity bra so that you stay comfortable as your breasts get bigger. You may need to buy more than one bra during your pregnancy as your breasts change size.

Nursing bras

If you’re planning to breastfeed, towards the end of your pregnancy you may want to buy a nursing bra. Some have a fastening so the cup can drop down, while others are made of stretchy material that can be lifted over the breast.

Try on different styles and try opening the cups under your clothes to check for comfort and convenience.

Caring for your bras

You can usually put bras in the washing machine, but some manufacturers advise that it’s better to handwash them.

Machine washing and tumble drying can affect the shape and support of the bra over time. Follow the care instructions on the label, and check occasionally that any underwires are in place and the shoulder straps still have their stretch.

Bras can stretch with time, particularly if you’re wearing and washing them regularly. If your bra no longer fits well, it’s time to replace it if you can.

Your breasts can also change size and shape many times during your life.

They can be affected by:

• Puberty
• The menstrual cycle (having periods)
• Pregnancy and breastfeeding
• The menopause (when periods stop)
• Getting older
• Weight changes

Because your breast size can change, it’s recommended that you go for a fitting or measure your bra size regularly. If you know you’ve experienced weight changes or changes to the size of your breasts, it’s a good idea to book a bra fitting.

If you’ve had surgery for breast cancer you may want more specialised help with finding suitable bras. See our information about bras after breast cancer surgery to find out more. Our booklet Breast prostheses, bras and clothes after surgery also has lots of information and helpful tips.

While an ill-fitting bra can cause discomfort, there is no link between wearing an ill-fitting bra and breast cancer.