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Bra Fitting Guide

All women deserve to be in a correctly fitting bra that is the right size for them. Many however, are not wearing the correct size. It is estimated that 80% of women wear the wrong sized bra – and although some know that they need to adjust the size they wear, many just accept their current fit because ‘bras are always uncomfortable’ or ‘their boobs are too big to have a nicely fitting bra’.

Wearing a correctly fitted bra in the right size can make a real difference to how you look and how you feel. Your posture will be improved, which in turned enhances your shape and the way your clothes hang – who would think that such a change could occur just by correcting your bra size!

So how can you ascertain if you are in the correct size bra, or what you may need to change to correct the fit?


As a starting point, make sure that you are wearing your current bra correctly. Slip your arms into your bra and before doing it up, lean forward and make sure that the wires are positioned under your boobs. Now stand up straight and fasten the hook and eye so that you have a snug, but comfortable fit. With a new bra, this should be possible by having the hook and eye on the loosest fitting to give room for tightening the band as the bra stretches due to repetitive wear. You should then lean forward once again and move the breast from the underarm so that it is inside the wire. Stand upright and gently push your boobs apart at the centre if necessary so that the centre front of the bra is sitting correctly between the breasts. Finally, adjust the straps so that they are firm, but not too tight.


When your bra fits you correctly, most of the support for your boobs (around 80%) should come from the bra band, with only 20% of the support coming from the shoulder straps. It is essential that you are wearing the correct band size so that more of the weight of your boobs is taken beneath them, and less by your straps.

Wearing your bra stand sideways and look in a mirror.  Is the band running around your back at the same level as the bottom of your bra cups? Or is it riding up your back? 

If the bra is riding up your back, the band is too large and you will need to go down by one or more band sizes.

If your band is too high at the back, it follows that your boobs will be too low at the front. Correcting the band size can get rid of the ‘droop’ and give you the uplift you are worthy of.

If the band is uncomfortably tight and the hook and eye is straining, then the band size is too small.


It is really important that your boobs are totally encased within the wire. The wire should not be sitting on, and therefore trapping the breast tissue.


The top edge of the bra cup should lay flat against your boobs and not cut in. There shouldn’t be any bulging at the neck edge and if you have a ‘four boob effect’ a larger cup size is needed.


f you have overspill under your arms, or if your boobs are falling out below the wire, you also need to increase the cup size.

The wire should also sit close to your chest. If the wires stick out at the centre front you need to adjust the cup size. Increase the cup size if your boobs are squashed against the wire. Alternatively, if there is too much wire for size of your boobs, you may need to go down a cup size, or try a plunge style.

If the wires are digging at your underarm a larger cup size is needed or a change of style.


If the cups are wrinkling and/or there is gaping at the top or the sides of the cup, a smaller cup size may be needed. It is also possible that the cup may be correct, but the shoulder straps need tightening.

 Try tightening the straps first (not too tight, you need to be able to get two fingers between the strap and your body at the top of the strap). If this does not solve the problem are smaller cup size, or a change of style, is needed.


If the straps are digging in to your shoulders, they are supporting too much breast weight, which means that the band is not giving enough support. A smaller band size may be needed.

If the straps continually fall down, they need to be tightened so that they are comfortable but not too tight. If your shoulders are quite rounded, you may want to look at bras which convert to a racerback, or adding a racerback converter to your bra.


When lifting your arms, your bra should stay in place. If the cups lift away from the chest when the arms are lifted, then either a smaller back size and/or a larger cup size is needed.

Often bras are thought of as being uncomfortable because they are moving around. By getting the correct fit, movement will be eliminated and comfort ensues.


It is very common for women to have one breast larger than the other. Sometimes the difference is only slight, but sometimes there can be a difference of one cup size or more. It is important to fit the bigger breast so that it is encased by the wire. The straps can be adjusted so they are looser on the larger side and tighter on the smaller side to achieve the best fit.


If you adjust your band size either up or down you may also need to adjust your cup size, this is because equivalent cup sizes adjust with the change in band size .

Example 1: You are wearing a 34E and the cup is fine, but the band is riding up a bit. You want to try a 32F

Example 2: You are wearing a 34F and the band is cutting in and too tight, but the cup is fine. You want to try a 36E

Example 3: You are wearing a 34D and the band is much too loose and the cup too small. You could initially try a 32E, or maybe even a 30F.

If the cup was fine a 34D would be a 32DD, but the cup is too small leading us to a 32E. If the 32 band is still too loose but the cup OK, the next size to try would be 30F.

Every bra size has ‘Sister Sizes’. And, as with the above example, one of the Sister sizes for a 32E is a 30F. What makes them ‘related’ is that each cup holds equivalent volume. Bra Sister Sizes can be seen in the table below.


Once the correct bra size has been found, it is a good idea to try a t-shirt on over it to see the difference in shape and check that the style suits with no bulging.


Having found the perfect fit in a certain bra, this does not mean that every bra in the same size will fit the same, or suit you. Brands, styles and colours can all fit differently.

You can also have exactly the same measurement as your friend, but what suits and fits them may not fit or suit you due to differences in bust shape – we are all unique!