When it comes to bra fitting advice, there’s a lot that can be said about cup size. From cups that cut in to ones that are gaping, it’s easy to find guidance for your cup-fitting woes. But those are only half of the story. The fit of your bra’s band is equally important – in fact, perhaps even more so.

Why is a firm-fitting band important?

It’s the band, not the cups or the straps, that does the majority of the supporting in a bra. And to do its job properly, it needs to be snug. The looser your band, the closer the bra is to simply hanging off your shoulders. And if the full weight of your bust is suspended from only the straps, that’s when they’ll start digging in – especially for those with large, heavy breasts. If your bras make your shoulders ache, your band size could be the problem.

It’s not just the comfort of the bra that a loose band can affect though, but the shape of it too. Since a too-loose band can’t provide enough support, the cups will inevitably droop down. But when it’s tight enough that it can’t slip around, the band anchors the whole bra in place, providing a robust and sturdy base for the cups to sit on. So if it’s lift you’re looking for, you need a firm band.

How to buy the right band size

A good place to start is simply with a measuring tape. Wrap it around horizontally at the breast crease or base of your breasts, pulling it comfortably firm. This number, in inches, is a band size to try on (if it’s odd, try both the size down and the one up from it).

However be aware that a number of factors affect your bra band size, and you may actually need to go one or two sizes above this starting point, or below it. For example, if you have a ‘solid’ ribcage – one that’s muscular or with bones close to the surface – you may need a larger band for comfort. And conversely, if it’s soft and squishy, you may need a smaller band size to achieve that same, nicely-snug fit. If in doubt, a bra fitter can help you decide.

And while we’re here, a quick tip: make sure you’re trying these bras on with the hooks fastened at the last (biggest) column. Over time, the elastic in the bra gives way and the band stretches out. So by starting with one that fits best at its loosest, you can gradually move the hooks inwards to compensate and maintain that same size.

But how tight is too tight?

So we’ve established that yes, your bra band does need to be firm. It’s crucial for support, to reduce strain on your shoulders. But tighter is not always better! Once you think you’ve found the right size, try this test: pop a couple of fingers inside the band at the back, and pull it away from your body. If you can pull it about an inch or so, it’s just right. If you can pull it rather a lot more, it’s too large.

But if you can’t pull it at all, or even struggle to get your fingers in there, it’s too tight. Your ribcage expands and contracts through the day as you breathe and move around, and so the band does need some ‘give’. Otherwise, it may chafe. And if your bra is hurting you, it’s definitely not the right size.

Overall, it’s a case of weighing up comfort vs support. Your bra band should be snug, but not painful. And if you feel like your bra band is already as tight as you’d want it, remember that you can also increase support from the band by choosing a wider, longline style. A very narrow band can simply cut in, without providing much support at all!