We all know how uncomfortable an ill-fitting bra can be. Between straps falling off your shoulder and a band that is just a smidge too tight, some days it can be unbearable.
A correctly fitting bra should provide “lift, support and most importantly, comfort” says Nala co-founder Chloe de Winter. “All breasts are different in size and shape so getting the right size is crucial.”
So, how do we make sure that we’re wearing the right size bra? Well, there are ways to measure to figure it out, but ultimately it comes down to trying and testing. Shape, padding and even the seam and stitching of each bra will determine how the bra fits.
So whether you have a small bust or large bust (or something in between), read on to find out how to find the right bra size.

Measure the underbust and overbust
When measuring your bust size, it’s best if you can get someone else to measure you. Having someone else assist will allow your body to fully relax and find an accurate measurement in a regular standing position. However, you can also complete the measurements on your own if necessary.
Here’s how to get your correct measurements:
- Start by using a measuring tape to measure your underbust — the area directly below your bust where the band of your bra would sit. This measurement will provide your band size.
- Repeat the process with your overbust, or the fullest part of your bust (usually in line with the nipple). This will be an indicator of your cup size. With both measurements, ensure the tape measure is pulled firm, as this is how the bra would naturally fit.
- Once you have both measurements, you can use a bra fitting guide to find the right size for you. If you’re looking to skip the calculations, Berlei offers a bra size calculator that will give you a recommended bra size based on your measurements.

What to look for when trying on a bra
When trying on a bra, there are several ways to ensure that the sizing is correct.
First, check the band size. Start on the loosest hook, so as the bra stretches you will be able to tighten and adjust, extending the life of the garment. The band should sit flush with the body and only have one or two inches of give when pulled from the back.
A good test is to raise your arms above your head, and ensure there is no movement of the band. If the band is too loose, it may rise up at the back or front, exposing some of the breast tissue. Alternatively, if the band is too tight, it will dig into the skin and may cause chafing and pain around the ribcage.
Next, look at the straps. They should be tight enough that they aren’t slipping off your shoulders, but loose enough for two fingers to slide under the strap comfortably. If you notice marks on your shoulders after wearing the bra, the straps might be too tight.

You also want to check the cup. Your whole breast should be enclosed in the cup, and you shouldn’t see any bulging over the top or sides of the bra. If you are spilling out of the bra, it is a sign to try the next cup size up.
Alternatively, if you notice areas of gaping or sagging in the cup, it is likely too big and you should try sizing down. Also, ensure that the centre panel between the cups is sitting flush and comfortably against the breast bone.
It is also important to check that the underwire is not digging into the skin at any uncomfortable angles. It should point towards the middle of the armpit, but not sit so high that it digs in and causes pain.
How do different styles alter the fit of a bra?
Unfortunately, each bra (and brand) will fit slightly differently, so it can be difficult to say that you are a certain size across the board. For example, some European brands will skip a DD cup, and go straight from D to E. This means that those who are normally a 14DD become a size 14E and so on.

There are also sister sizes to consider. This means that by going up a band size, you drop a cup size, or vice versa. Theoretically, a 16F will fit the same volume of breast tissue as an 18E. However, sister sizes will only work if the band is still a correct fit.
Different bra styles will also vary in how they fit. A balconette bra will support the breast from underneath, whereas a side support bra will provide forward projection.
The style of bra you choose comes down to personal preference. So, where possible, head in-store to try a variety of styles to find what works best for you.
It is recommended to be refitted every six months to one year. Breast size can change based on weight gain or loss, pregnancy, hormonal changes and age. So, refitting ensures that you are comfortable and supported in your chosen bra.
If you’re looking for a perfect fit for a larger bust, check out our recommendations here.