Online Tools

    Bra Size Calculator

    Estimate a starter bra size from underbust and full-bust measurements, then compare US, UK, EU, FR, IT and JP labels with sister-size options.

    Measure snugly around the ribcage, keeping the tape level.
    Measure around the fullest part without pulling the tape tight.
    Starter size from measurements:
    34C
    difference: 16.5 cm - cup C
    US
    34C
    UK
    34C
    EU
    75C
    FR
    90C
    IT
    3C
    JP
    75C
    Sister sizes
    Sister sizes keep a similar cup volume while changing the band. Use them as try-on alternatives, not as a guaranteed fit.
    Tighter band
    32D
    -1 band, +1 cup
    Starter
    34C
    from measurements
    Looser band
    36B
    +1 band, -1 cup
    full bustunderbust band
    Measurement zones
    Full size table
    Bra size conversion table
    UnderbustUS/UKEU/JPFRITCup AACup ACup BCup CCup DCup ECup FCup GCup HCup ICup J
    63-67 cm306580130AA / 65AA30A / 65A30B / 65B30C / 65C30D / 65D30DD / 65E30DDD/F / 65F30G / 65G30H / 65H30I / 65I30J / 65J
    68-72 cm327085232AA / 70AA32A / 70A32B / 70B32C / 70C32D / 70D32DD / 70E32DDD/F / 70F32G / 70G32H / 70H32I / 70I32J / 70J
    73-77 cm347590334AA / 75AA34A / 75A34B / 75B34C / 75C34D / 75D34DD / 75E34DDD/F / 75F34G / 75G34H / 75H34I / 75I34J / 75J
    78-82 cm368095436AA / 80AA36A / 80A36B / 80B36C / 80C36D / 80D36DD / 80E36DDD/F / 80F36G / 80G36H / 80H36I / 80I36J / 80J
    83-87 cm3885100538AA / 85AA38A / 85A38B / 85B38C / 85C38D / 85D38DD / 85E38DDD/F / 85F38G / 85G38H / 85H38I / 85I38J / 85J
    88-92 cm4090105640AA / 90AA40A / 90A40B / 90B40C / 90C40D / 90D40DD / 90E40DDD/F / 90F40G / 90G40H / 90H40I / 90I40J / 90J
    93-97 cm4295110742AA / 95AA42A / 95A42B / 95B42C / 95C42D / 95D42DD / 95E42DDD/F / 95F42G / 95G42H / 95H42I / 95I42J / 95J
    98-102 cm44100115844AA / 100AA44A / 100A44B / 100B44C / 100C44D / 100D44DD / 100E44DDD/F / 100F44G / 100G44H / 100H44I / 100I44J / 100J

    Estimate Bra Size Across US, UK and EU Systems

    English search results for bra sizing expect a measurement-first calculator, not only a regional chart. This tool estimates a starter band and cup from underbust and full-bust measurements, then shows common US, UK, EU, FR, IT and JP labels.

    Use the result as a fitting starting point
    Bra fit changes by brand, cup shape, wire width, strap placement and personal comfort. Treat the calculated size and sister sizes as try-on options, then compare the retailer's own fit guide.

    Measurements, Cups and Sister Sizes

    • Measure the underbust snugly around the ribcage to estimate the band.
    • Measure the full bust without pulling the tape tight to estimate the cup.
    • US, UK and EU cup labels diverge after D, so the calculator keeps each system visible.
    • Sister sizes keep a similar cup volume while moving one band size tighter or looser.

    The calculator converts inches to centimeters internally before matching the closest cup interval.

    Frequently Asked Questions

    Sources and References

    Calculations are based on the listed reference sources. Links open in a new tab.

    Updated:

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