When buying a first bra, many parents assume a professional fitting is essential. But the truth is, professional bra fittings are designed for adult bodies — not for tweens and teens who are still growing and changing.
And even adults only require a tape measure and an open mind! (Adults are often wearing the wrong size bra because they've grown up wearing a certain size and reluctant to change). Did you know that an 8D cup size is SO much smaller in cup size and volume than a 14D? You might look at the 8D woman and incorrectly think she is an A or B cup. And often, for this reason and due to this lack of knowledge, women are wearing band sizes two big and therefore, cup sizes too small.
For most bras for teens, comfort, flexibility, and room to grow matter far more than precision sizing.
Bra sizing isn’t universal — even with professionals
Sizing varies significantly between brands. A size that fits well in one brand’s teenage bras may feel completely different in another.
Even the most experienced fitter can only work with what’s in-store — often fitting teens into available stock rather than what best suits their stage of development.
This is why flexible, wirefree designs are often the best bras for teens.
Comfort matters more than an exact size (which will probably change tomorrow anyway!)
If a bra isn’t comfortable, it won’t be worn — regardless of how technically “correct” the fit is.
The best bras for teens focus on:
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softness
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breathability
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freedom of movement
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minimal seams and no poking
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less heat trapping under school uniforms
Trying bras at home allows teens to move, sit, stretch, and live in them - something a fitting room can’t replicate.
Most teens don’t need wires, padding, or moulded cups
Underwire, moulded cups, lace, and heavy padding are uncomfortable and not functional.
For teens, these elements can feel restrictive, trap heat, and irritate sensitive skin. Well-designed wire-free bras for teens can still provide coverage and great support - without forcing a growing body into a fixed shape.
Professional bra fittings aren't made for growing girls.
Professional fittings are most useful for people who:
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have finished growing
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wear underwire bras
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use moulded or padded cups
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need precise sizing to avoid discomfort
These needs rarely apply to tweens bras or teenage bras, which should prioritise comfort over structure.
Early bras aren’t about lift or shaping — they’re about coverage, confidence, and ease.
Teen bodies change too quickly for precision sizing
Teen growth is unpredictable. Ribcages expand, breast tissue develops unevenly, and growth spurts can happen fast.
A professional fitting captures one moment in time. That “perfect size” can become uncomfortable within weeks, making repeat fittings frustrating and unnecessary when choosing a first bra.
For bras for teens, adaptability always beats precision.
Sizing up doesn’t mean more wear
It’s common to size up when buying a first bra, hoping it will last longer.
In reality, a bra that’s too big often feels awkward and less supportive. The best bras for teens are designed to stretch and move with the body, meaning a closer, comfortable fit usually lasts longer than an oversized one.
Designed with room to grow
Billie Green bras are intentionally wirefree, softly yet supportively structured, and made with gentle stretch and premium fabrics that give a little. Our tweens bras and teenage bras are designed to comfortably span multiple similar sizes, allowing teens to grow without constant re-fitting.
An important reminder: no one needs a bra
No one is required to wear a bra.
The right time to start wearing a first bra — and the right style — should always be led by the teen. Comfort, choice, and confidence come first.
The takeaway
Professional bra fittings aren’t harmful but they can be demoralising and awkward. And for most teens, they’re unnecessary.
When choosing bras for teens, aim for comfort, flexibility, and bras that are designed for growth (wirefree, premium/soft fabrics) . And more often than not, the best place to find out what fits the best is to try it out at home.
