Wonderbra Size Guide

Bra Size Guide: How to Measure Your Bust for the Perfect Fitting Bra

Bras are specifically designed so that women feel supported! We all know that people come in different shapes and sizes, just like breasts. Knowing your bust measurements and wearing appropriate underwear based on your figure can make a huge difference. It will help you feel confident and comfortable without worrying about any pain or lines from your bra being too tight.
Women often struggle with their bras, mainly because they’re wearing the wrong size.  Studies have shown that 80-90% of women wear the wrong bra size in the UK.

To find your bra size, look at our guide below.

Why it’s Important to Wear a Bra that Fits

By wearing a bra that fits you correctly, you’ll feel much more empowered! The comfort and support provided by the right bra are second to none. 


However, it’s also a matter of health. Women who wear the wrong bra size often suffer from pain in their shoulders, neck and back, leading to further problems such as bad posture. This can then lead to further problems such as bad posture. 


These are the main reasons why wearing a bra that fits is so important. If you’re unsure what a bra that fits looks like, keep reading.

When Was the Last Time You Measured Your Bra Size?

Women wearing the wrong bra size,  often do so because they don’t know what’s right for them. Either the band is too large, and the cup size is too small or vice versa. This tends to happen because women get measured once and believe that is their bra size for life. 

However, your body and breasts naturally change over time! Regularly measuring yourself is key to knowing your correct bra size. It’s recommended that you have yourself measured every 6 months. But exactly how do you measure your bra size? 

Keep reading our tips and tricks, and use our interactive size guide to find the perfect fitting bra!

How to Measure Your Bra Size at Home

Although you can visit stores and book an appointment with a bra fitter, measuring yourself at home is easy! All you need is a soft tape measure, and the interactive Wonderbra size guide will do the hard work for you.

1. Start by wearing a non-padded t-shirt bra so your breasts are in the right position.


2. To find your band size, place the tape measure around the ribcage just where your bra's band sits, ensuring it is firm and straight around your body.


3. Check to see how many inches you are. An even number will give you your band size. If it lands on an odd number, round up by one (if you're halfway between, go to the nearest whole number and apply the same rule)

4. Now place the measuring tape around your bust at its fullest part (horizontally at the nipples).

5. To calculate your cup size, simply minus your band size from this number and figure out what you’re left with (1 = A, 2=B, 3=C).


Putting this into practice, if your bust circumference is 33 inches and your chest circumference is 36 inches, start by shopping for 34C bras. 

Different brands will have different fits and sizing, so you may not be a 34C in every brand. Get the fit right by reading our fitting tips to make sure the size is right for you. 

Bra Size Chart: How to Measure Cup Size

Bra Sister Sizes

Did you know that your bra size also has a sister size? This is where the band size and cup letter change, but the actual cup volume remains the same. 

If you haven't quite found the perfect fit on the band, but you think the cups fit, then you can often get away with sister sizing your bra up or down by one! 

What the Perfect Fitting Bra Looks Like

As we’ve already mentioned, all breasts are different! Therefore, a bra that fits one woman may not fit the same on another as she has slightly different shaped breasts - even if they’re the same size. 


Not only do you need to find a size that fits, but you also need to consider the different styles that are available too.


As a general rule of thumb, to know your bra fits, you should notice:

1. The band around the back sits firm (this should be tight but not uncomfortable)
2. The wire should be flat against the ribcage, not resting on any breast tissue
3. Breasts are encased by the cup, meaning no gaps or spilling over
4. There is no bulging along any of the bra
5. The straps don’t fall down or dig into your shoulders

Here’s a little tip: try lifting your arms. If the bra stays in place, chances are you’ve found the perfect size and style!

International Bra Size Converter

The bra size calculator helps you find your UK bra size. If you’re shopping internationally,  you’ll notice that bra sizing is different. Look at this international bra size conversion chart to know what size bra to buy outside of the UK.

Maidenform Shapewear Size Guide

Maidenform is a sister company of Wonderbra, offering high-quality and reliable shapewear solutions. Look at our size guides below to find shapewear that fits.