Google "bra size calculator" and you'll get a million different results, it can be very confusing. Around 80% of women are wearing the wrong size bra, mainly down to a lack of understanding about how bra sizing works, and how bras are meant to fit.
Many bra size guides and even some professional fitters will give you a band size which is far too big, often because they are still using vintage sizing which involved measuring the under-bust and adding several inches to get the bra size. (Just like dress sizes, bra sizing has changed over the years.) A band size 34, for example, is meant to fit approximately 34" under-bust, although how tight it feels depends on various factors including your own body type. The correct band size should be the smallest you can comfortably wear, which means that two people with the same measurements will not necessarily be the same size. Cup sizes are in proportion to the band size, so a D cup on a 36 band is bigger than a D cup on a 34 band.
Using the "traditional" method for calculating bra size in a modern bra results in a band size far too big, and a cup size which is too small - Don't be reluctant to try on a smaller band size and/or larger cup size. Many people feel intimidated by what are considered larger cup sizes, but once you have tried your true size you will see the difference! It is a common misconception that a woman with D cups is extremely well endowed. In fact, a D cup is about average.
Some oft-repeated bra myths:
- "The average bra size in the UK is a 36C." 36C is the most commonly worn size, but this does not make it the true average size by any means. Given that around 80% of women wear the wrong size bra, a survey of the bras we wear is almost useless in determining the average. Studies 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 actual average size is 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 true average cup size is at least a D, and a woman can be a DD, E or even F cup without looking much bigger than average. People often forget that cup size is relative - for example, a 28F would be roughly equal to a 36C in volume.
- "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. 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.
- "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 "normal" size is often based on the sizes they see 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.
- "A band size 32 is the smallest you can get, therefore it must be about a size 8." Many people don't realise that if you know where to look, band sizes actually go down to a 28, even in larger cup sizes. A band size 32 is closer to a size 12.
- "The number of the bra size is the bust measurement." Another myth arising from the confusion of bra sizing, and the changes in bra sizes over the years. In modern bras, the number is the band size and is meant to be your underbust measurement, not bust line. 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.
- "The bra should fasten on the smallest adjustment to allow you room to grow." This only applies to pregnant women, who will need to allow for the expansion of their ribcage. If you are still growing then you will almost certainly need a bigger cup size as well as a bigger band size, making it a pointless excercise to leave room to grow. Bras will stretch over time, 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 4-5 inches to your underbust measurement, then work out your cup size based on your bust measurement. This is your size set in stone." 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 under-bust 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!
- "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. Don't always take their 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 slim and/or a large cup size, they may well stick 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 tell you that you need 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! A better fitting bra will not dig in to the shoulders as much, and 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 a certain amount of red 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 clothes leave red marks on you - knicker elastic, the seams of your jeans, waistbands, pretty much anything short of a baggy t-shirt, 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 a firm fit. 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.
- 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 raise your arms, 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 size is far 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.
- You are able to fasten the bra at the front and easily twist it round. This method of putting a bra on should not normally be possible if you are wearing the right size. If you can comfortably twist the bra around your body after it has been fastened, it's probably too loose.
- The band feels roomy and you can easily fasten the hooks on the smallest adjustment, even when brand new. You should be able to run a couple of fingers around inside the band, but if you can stretch the bra out from your chest, it is too loose.
- Shoulder straps dig in. This often means the band is too big, forcing the straps to take the weight.
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 the armpits, 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.
Correct back size..................back size too big
Correct cup size.................cup size too small
So how do I find my true bra size?
There is a formula to calculate bra size, which some swear by, others take with a pinch of salt, and some distrust completely. However vague, it can be used as a starting point to calculate your theoretical size, as long as you examine the fit of the bra, and trust your experience over the maths. Once you become familiar with how your bras fit, you will no longer need to re-measure yourself if you change size.
Alternatively, you can work with your existing bra and determine through the fitting tips and warning signs given here whether you need to try a different band or cup size. If you’re suffering from any of the bra ailments mentioned above, you’ll probably already have some idea of what you need to change!
If you have no idea of your size or if you don’t already have a bra, you’ll need to find a tape measure and take your bust and underbust measurements. It helps to stand in front of a mirror to see what you’re doing and to check that the tape measure is horizontal
The underbust measurement should be taken by holding the tape measure horizontally underneath the breasts. Pull the tape measure fairly snug and don’t breathe in deeply. Don’t worry about it feeling too tight – the elasticity of the bra should take care of comfort.
When you take your bust measurement, take into account that wearing a cup size too small might squash your bust down and distort the measurement. If you don't have a bra, or if the one(s) you have are very ill-fitting, then try bending over so that your back is parallel to the floor, and measuring your bust in that position. Don’t pull the tape measure too tight when measuring your bust; in fact it should almost slip off.
If your underbust measurement in inches is a whole number, that will most likely be your band size. If not, then you will need to round up or down to the nearest even number, but which fits better can only decided by trying on some different sizes.
Once you have found your band size, subtract it from your bust measurement to find the difference between the two numbers. For each inch difference, you will need to go up one cup size. If your bust is less than one inch bigger than your underbust, you need a AA cup; if it's one inch bigger, you need an A cup, etc.
<1" = AA
1" = A
2" = B
3" = C
4" = D
5" = DD
6" = E
7" = F
8" = FF
9" = G
10" = GG
11" = H
12" = HH
13" = J
14" = JJ
15" = K
The cup size calculation will be less accurate for larger cup sizes.
You may be surprised at how big your true cup size sounds - if you have been wearing a band that's too big, you will have had to compensate by getting a smaller cup size.
- If you are going to get fitted, always go to a shop which stocks the full range of sizes. If you are smaller than a size 12, or if you have a larger than average bust, bear in mind that you might need a size which is unavailable in most shops, and the shop assistant may give you a bra in the wrong size in order to make a sale, or they may not even be aware that a better fitting bra exists. The best fitters examine the bra very carefully, and do not rely on a tape measure.
- Most people's breasts fluctuate in size, and they can sometimes grow for no apparent reason, so it's a good idea to review your size every six months or so.
- The correct band size is the smallest you can comfortably fasten around your back, and the right cup size is the biggest you can completely fill out with no gaping or wrinkles in the fabric.
- It's easier than you might think to wear the wrong cup size and not notice, and it's often only when you try on a bigger size that you realise the old size was too small. It's always a good idea to try on different cup sizes so you can actually compare.
- When trying on a new size, avoid bras that significantly alter the shape of your breast. It can be difficult to tell if they are meant to bulge out like that or if it's too small!
- A new bra should fit on the biggest adjustment to allow for stretch over time. If it already fits comfortably on the smallest adjustment, go down a band size (and up a cup size to compensate.)
- If you have uneven cup sizes, go with the bigger side. You can help to support the smaller side by shortening the shoulder strap, or if there is a significant difference, you may need to pad one cup.
- It's better to buy a new bra when on your period or just before, you're often bigger then.
- Always try on a bra before you buy, even if you think you know your size or you've bought that brand before.
- Don't forget to adjust the shoulder straps when trying on a bra. You should not have to make them very tight, as they are not intended to support the whole weight of your breasts. However, if you have one breast bigger than the other, you can help to support the smaller side by making that strap a bit shorter.
- If you find the bra lacks support unless you make the shoulder straps very tight, you probably need a smaller band size or a deeper, more supportive band. Most good bras tend to have at least 2 hooks (although there are always exceptions.)
- To test if a bra is supportive enough, stand in front of a mirror and take off the shoulder straps. The band should grip your body and not slip down at all. Check that the underwires are high enough at the sides to support the whole cup.
- Your breasts feel supported from your chest rather than your shoulders.
- They are positioned on the front of your chest and pointing forwards, not falling towards your arms.
- The cups are a perfect fit, with no wrinkles or bulges.
- The underwires surround each breast, not sitting on or digging in to any breast tissue.
- The band is a snug fit, tight enough to offer support. Fits on the biggest adjustment when you first buy the bra.
- Your bra doesn't weigh down on your shoulders, leaving painful red marks.
- You don't have to be constantly adjusting it.
- You feel your posture and silhouette are instantly improved.