Here's an uncomfortable truth: the vast majority of women are wearing the wrong bra size right now, and most don't know it. Not because anyone's careless, but because lingerie shopping comes with a few traps that are easy to fall into and genuinely hard to notice from the inside. If any of these sound familiar, you're not doing anything wrong — you're just human. Here's what to watch for.
1. Guessing your size instead of checking it
Bodies change — gradually, after weight shifts, after time. A size measured two years ago isn't necessarily your size today. Re-measure roughly once a year, and whenever something that used to fit suddenly doesn't.
2. Choosing for looks over how it actually feels
A beautiful piece that digs in, gapes or rides up isn't doing its job. Before you commit, move in it the way you actually would — reach up, sit down, breathe out. If it only looks right standing perfectly still, it's not right.
3. Owning one bra for every occasion
A single everyday bra can't also be your going-out bra, your under-a-backless-dress bra, and your lounging-at-home bra. A small rotation — one supportive everyday piece, one wire-free, one for special occasions — serves you far better than one bra doing five jobs badly.
4. Focusing on cup size and ignoring the band
The band, not the straps, does most of the actual support — which is why a bra that's riding up at the back almost always means the band is too big, whatever the cup size says. It should sit level and snug, not pulled tight by the straps to compensate.
5. Ignoring your actual shape
Not every style suits every shape, and that's not a flaw in you — it's just fit. Fuller coverage or balcony styles work beautifully for some shapes; plunge or triangle cups suit others. If a style never quite looks right no matter the size, it may simply be the wrong style, not the wrong size.
6. Assuming one size fits all brands
A 34C in one brand can fit completely differently in another — cut, fabric and construction all vary. Always check the specific brand's size guide rather than assuming your usual number carries over, especially when trying a brand for the first time.
7. Ignoring the fabric
Cotton breathes and suits everyday wear; microfibre smooths under clothing; lace looks wonderful but isn't built for all-day comfort. Matching the fabric to how long and how often you'll actually wear something saves a lot of post-purchase regret.
8. Wearing the same bra for years
Elastane loses its stretch with time and washing, usually before it looks obviously worn out. As a rough guide, most bras are ready for replacing somewhere between 6 and 12 months of regular wear — sooner if the band has gone slack or the straps won't tighten any further.
9. Machine-washing everything
Heat and tumbling are what break down elastane and underwire fastest. Hand washing in cool water, or a mesh bag on a cold gentle cycle, makes pieces last significantly longer — see our full care guide for the details.
10. Skipping the size guide and the return policy
Trying something on at home, over your own underwear and with tags attached, is a completely normal part of buying online — and knowing you can return it if it isn't right removes most of the risk from trying a new size or brand.
11. Treating lingerie as an afterthought
What's underneath affects how everything else fits and sits — a backless dress, a fitted top, a tailored blazer all look different depending on what's worn beneath them. A few minutes' thought here changes how the whole outfit works.
The quick version
- Re-measure yourself roughly once a year.
- Check the band fit, not just the cup.
- Check each brand's own size guide — don't assume your usual number.
- Hand wash where you can, and skip the tumble dryer entirely.
- Replace bras worn regularly every 6–12 months.
- Try at home, keep the tags on, and know the return policy before you need it.
Browse our Lingerie collection, or read our Hold-Ups size guide if hosiery fit is the mistake you keep making.