The sizes within the black outline are regarded as being the average range, and are the easiest to find on the high street. The blue section is often classed as large or plus sized, and the sizes in the pink box are considered to be small sizes, i.e. starter/first bras. As the table shows, a huge section of women are not represented by any of these three departments, and consequently most people do not realise that there is a far wider range of sizes in existence, than are made available by retailers. Band sizes go from 28 up to at least 56, and cup sizes start at AA and go up to K. Many people who have not been fitted base their estimate of their own size on what is considered to be average, often leading to wearing a band size which is far too big, and a cup size which is too small. The shaded area represents a more realistic estimate of the range of most common sizes.

Some oft-repeated bra myths:

"The average bra size in the UK is a 36C." More bras are sold in 36C than any other size, but this does not make it the true average size by any means. Given that as many as 95% of women are wearing the wrong size bra, a survey of the bras we wear is almost useless in determining the average. Research by Bravissimo found that 60% of C cup wearers should be at least a D cup, and more than half of us are wearing a back size which is too big. The true average size is estimated to be around 34DD.

"Most women are around a B-C cup. DD cups = huge. FF cups = fake." In fact, many women are a much bigger cup size than they think because wearing the wrong back size skews the cup size. The average size is around a DD, and a woman can easily be an E or even F cup without looking much bigger than average. People often forget, or are unaware, that cup size is relative - for example, a 28F would be roughly equal to a 36C in volume, and four cup sizes smaller than a 36F.

"A 32 is small, a 38 is big." It's not as simple as that; the band size is only the size of the ribcage and bears no relation to the size of the breasts or the woman's body shape. Someone with a 32" band is just as likely to have DD cups (or even E, F, FF etc) as someone who wears a 38. This misconception may be due to the fact that many people incorrectly assume the number in the bra size is the bust measurement.

"A pair of D-cup breasts weighs around 15 to 23 pounds." Anyone who understands how bra sizes work will see how ludicrous this claim is. Cup size alone is meaningless without the band size, so this does not give any indication of volume per se. In any case, this statistic gives a very distorted image of how big D cups are. In order to weigh this much, the band size would have to be very large indeed! One source [link] claims that a typical 36C breast (equivalent to a 34D) weighs 0.9kg which equates to just under a pound each - a much more realistic estimate!

"No-one with a small band size has big boobs unless they're fake." As mentioned above, there is no reason why someone with a small band size cannot have a large cup size. People's idea of what constitutes a "normal" size often comes from the sizes available in the shops, so it is understandable that many people equate small band sizes with a flat chest, and large cup sizes with a fuller figure because it's often only the pre-teen bras which go smaller than a 32 band size, and only the plus size bras which go bigger than a DD cup.

"The number of the bra size is the bust measurement." Another myth arising from the confusion of bra sizing. The number in the bra size is the band or back size, and refers to the size of your ribcage, not your bust. If your breasts grow, you need to go up a cup size, not a band size. You only need to get a bigger band size if the one you are wearing is too tight to fasten.

"A band size 32 is the smallest you can get, so it must be around a size 8." Many people don't realise that band sizes actually start from 28, even in larger cup sizes. A band size of 32 is usually closer to a size 12, and if a woman has a large cup size, she could be wearing a size 14-16 and still need a 32" bra.

"The bra should fasten on the smallest adjustment to allow you room to grow." There is little point in allowing room for growth, as your cup size is far more likely to change with weight gain than your band size. Bras will stretch with wear, so if it already fits you on the smallest adjustment, it will quickly become too big. The purpose of the adjustable back is to allow for this stretching.

"To get your bra size, you have to add 4 to 5 inches to your underbust measurement, then work out your cup size based on your bust measurement. This is an accurate way of determining your size." Adding this much to your underbust measurement would mean your bra would ride up your back and offer hardly any support, especially if your breasts are heavy. If you are trying to get an idea of your bra size from your measurements, then you should just round your underbust measurement to the nearest even number. Quite apart from that, no formula will work for everyone so the right size is the one that fits!

"Women with an underbust of less than 33 inches should add 4 or 5 inches to their measurement, and those with an underbust of 33 inches or more should add two to three inches." This is little more than a ploy to sell a narrow range of sizes to a wide range of consumers. It is possible to convince someone who needs a 28 band size that they will manage with a 32, but of course it would be impossible to fit someone who needs a 38 into a 34, thus the standard size range of 32-38 (just four different sizes!) is marketed to all. There is also an association between large band sizes and large cup sizes, so they are perceived as needing more support and thus a tighter band.

"The shoulder straps support the breasts." Most of the weight of the breasts should be supported by the band around the chest, not the shoulder straps. The bra relies on the tension of this band to support the cups, and this is why it's so important that you wear the correct back size.

"The size that the lady in the shop tells you is always the right one." While it is always a good idea to get fitted, it is also important to bear in mind that some fitters are better than others. A 2004 report by consumer watchdog Which? found that almost 80% of bra fittings resulted in a poor fit. Don't always take the fitter's word for it - try on a range of sizes to see for yourself and compare with the pointers in this guide. Many shops only stock the "average" sizes, so if you are quite slim and/or a large cup size, they may well put you in the smallest band size and largest cup size they have despite it still not fitting. For example, if you should be a 28F, they might put you in a 32DD. It is advisable to go to a shop which stocks a wide range of sizes. Bravissimo and Rigby & Peller are highly recommended for bra fitting.

"If the shoulder straps dig in and your back hurts, it means you have very heavy breasts and there's not much you can do about it short of getting a breast reduction." If you are suffering pain because of a heavy bust, it's probably your bra, not you, that needs to change! NHS studies have found that as much as 100% of patients requesting breast reduction were wearing ill-fitting bras. [link] A better fitting bra will support from the chest and not dig into the shoulders as much, so there may not be any need to resort to surgery.

"A certain amount of spillage is ok - that's what push-up bras are meant to look like anyway." Any amount of spillage in any type of bra means the cup size is too small. Even if you have cleavage, there should still be a smooth line at the edge with no "double boob" effect.

"If your bra leaves red marks around your chest, it means the band size is too small." The truth is that any bra will leave some marks, even if it's quite comfortable. If the band is so loose that it leaves no mark on your skin at all, it's probably too big. Think about how many other types of clothing leave red marks and indentations on you - knicker elastic, the seams of your jeans, waistbands etc but nobody ever says that means they're too small!

"The band is meant to be "comfy" and not too tight." The band of your bra is actually meant to be quite tight. Not so tight that it is painful, of course, but tight enough that it won't move around much.

"If the back and sides of your bra make your flesh bulge, it's too tight." Bulges around the band of your bra are not necessarily a sign that you need a bigger band size. Wearing a smaller band size can actually reduce bulging, as it will be positioned lower on your back.

Signs that you're wearing the wrong band size:

The band slides about and rides up at the back. The band of the bra should be horizontal all the way round and quite a snug fit. If you pull the shoulder straps upwards, the band should grip your back. If it slides up easily, or if your boobs pop out under the bottom of the bra, the band is probably two or more sizes too big.

You're always having to pull the back of the bra down. This could be a sign that it is riding up and you need a tighter band.

The band feels roomy and you can easily fasten the hooks on the smallest adjustment, even when brand new. The band of your bra needs to be a snug fit in order to support the cups, and it should fit on the biggest adjustment so that you are able to tighten it when the elastic starts to wear out. If it fits firmly against your body, but you have to fasten it on the tightest adjustment straight away, it's probably one size too big (see the centre image below.)

You can stretch the back of your bra away from your body by several inches. You should be able to run a couple of fingers around inside the band to make sure it is not cutting in, but if you can fit more than a fist under the back, it's too loose.

The shoulder straps dig in. This often means the band is too loose, forcing the straps to take the weight.

The shoulder straps are constantly slipping off. This can be a sign that the band is too big, and therefore designed to fit a larger frame with broader shoulders. The shoulder straps on a smaller band size will be positioned closer together. If you find that you have to loosen the straps to prevent them from cutting in, this is also due to the band being too large and not supportive enough.

Signs that you're wearing the wrong cup size:

The top edge of the cups make a double bulge. The cups should make a smooth profile, even in push-up styles. If you are spilling out, even a small amount, try a bigger cup size.

The underwires do not lie flat against your sternum in the middle. This is another sign that the cup size is too small, as the breasts are not being contained within the cups and are forcing the centre of the underwires out from your chest (a look often sported by page 3 girls.) If you want to enhance your cleavage, look for a bra designed for this purpose in the right size.

The underwires sit on or poke into breast tissue at any point. This means they are not fully enclosing the breasts. Don't forget to check the sides of the underwires under your arms, they should lie flat against your ribs in the same way that the centre lies flat against the sternum, with no bulging or spilling out.

The fabric of the cups is wrinkled and loose or there is a large gap at the top. This means you're not filling them out fully, so you should try a smaller cup size.