Yes. Bra Size is free worldwide with no sign-up, no app download and no region restrictions.
It gets you very close using two measurements, but fabric stretch, wire shape and how a brand cuts its cups all shift the final fit. Treat the result as your starting point for trying sizes, not a guarantee.
Every brand uses its own block pattern, so a 34B in one label can fit like a 34C in another. This is completely normal and is exactly why sister sizes exist.
That rule is outdated. It was created decades ago for stiffer fabric. Most fit specialists today use your direct underbust measurement as the band size, which is the method used on this site.
A sister size carries the same cup volume in a different band. Moving one band size up and one cup letter down (or the reverse) keeps roughly the same volume — handy when your exact size is out of stock.
Every 6 to 12 months, and always after a significant weight change, pregnancy, breastfeeding or surgery, since band and cup size both shift over time.
There has never been a single global standard above a D cup, so the US and UK diverged decades ago — a US DD is a UK E, and it keeps shifting by roughly one letter as sizes go up.
No. Japan's JIS standard measures cup difference in centimetres rather than inches, with each 2.5cm of difference moving one cup letter, so a Japanese size doesn't translate one-to-one with a US or UK size.
Australian retailers typically follow the same band-inch, UK-style cup lettering as the UK, so the two are usually very close.
EU and French band sizes are given in centimetres rather than inches. A US/UK 34 converts to roughly a EU/FR 75, with cup letters generally following the UK convention.
Not necessarily. A band that's too big rides up at the back and stops giving support, forcing the straps to carry weight they were never meant to hold. The right band sits level and snug on the loosest hook.
Elastic naturally relaxes with wear and washing. This is normal and is exactly why bras come with multiple hook rows — move to a tighter hook rather than sizing down.
Generally yes, the band and cup numbers are the same system, but wire-free and soft-cup styles can feel roomier, so some people size down the cup in wire-free styles.
Yes. The band-and-cup system describes volume and circumference, not shape, so breast shape, root width and projection still change how the same labelled size sits on different people.
Both can shift, but the underbust measurement is generally more stable, while cup volume tends to respond first and most noticeably to weight change, pregnancy or breastfeeding.
Yes, mild asymmetry is extremely common. Fit the cup to the larger side and use a thin insert on the smaller side if needed, rather than sizing based on an average.
The band should sit level and stay in place on the loosest hook, the centre gore should lie flat against the breastbone, and the cups should fully contain the tissue with no spilling or gapping.
There's no single global standard above a D cup, so brands choose their own labelling — some use DD, others DDD or E for the same volume. Always check that brand's specific chart if you're between systems.
Use your measured size as the starting point either way. Padding adds shape rather than volume, though very thick padding may fit best a cup size down if it feels tight across the top.
Try the sister sizes shown with your result first — they carry the same cup volume in a more commonly stocked band.
The number is your band measurement in inches (or centimetres, depending on the region) and the letter is your cup size, describing the difference between bust and band — not an absolute volume.
Many sports bra brands use their own size charts, often S/M/L or a mix of band and cup, since compression and coverage needs differ from everyday wear. Check the specific brand's chart.
Yes. Wear a well-fitted, non-padded bra, stand naturally in front of a mirror, and keep the tape level and parallel to the floor for both measurements.
Hormonal changes can cause mild, temporary swelling, so if possible avoid measuring right before or during your period for the most consistent result.
The same measuring method works at any age, but bodies can change quickly during teenage years, so more frequent re-measuring is normal and expected.
Not a separate one — most Indian retailers use the same inch-band, UK-style cup lettering as the UK. Our calculator's IN tab shows it labelled that way.
Many Southeast Asian markets don't have one official national standard and instead follow whichever import convention — US, EU or Japan-style — their retailers stock most, so treat our result as your closest starting match rather than a guaranteed national size.
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