{
    "name": "Bra Size Calculator",
    "url": "https://calculators.geekmidst.com/calculators/bra-size-calculator",
    "markdown": "https://calculators.geekmidst.com/calculators/bra-size-calculator.md",
    "category": "Everyday tools",
    "description": "Find your European bra size from underbust and bust measurements in cm or inches, using the EN 13402 band and cup ranges.",
    "summary": "European bra sizes come straight from two tape measurements: the band is your underbust rounded to the nearest 5 cm, and the cup letter steps up every 2 cm of difference between bust and underbust.",
    "also_called": [
        "EU bra size calculator",
        "Cup size calculator"
    ],
    "applies_to": "Worldwide",
    "last_updated": "2026-10-29",
    "computation": "Results are computed in the visitor’s browser on the HTML page. This API describes the calculator; it does not compute results.",
    "inputs": [
        {
            "name": "unit",
            "label": "Measurements in",
            "type": "segmented",
            "default": "cm",
            "options": {
                "cm": "cm",
                "in": "inches"
            }
        },
        {
            "name": "underbust",
            "label": "Underbust (snug, around the ribcage)",
            "type": "number",
            "default": "87"
        },
        {
            "name": "bust",
            "label": "Bust (around the fullest part)",
            "type": "number",
            "default": "107"
        }
    ],
    "outputs": [
        {
            "key": "size",
            "label": "European size (EN 13402)",
            "format": "text"
        },
        {
            "key": "band",
            "label": "Band",
            "format": "integer"
        },
        {
            "key": "cup",
            "label": "Cup",
            "format": "text"
        },
        {
            "key": "difference_cm",
            "label": "Bust minus underbust",
            "format": "number"
        }
    ],
    "formula": {
        "text": "Band = underbust rounded to the nearest 5 cm;  Cup from (bust − underbust): over 10–12 cm AA, 12–14 A, 14–16 B, 16–18 C, 18–20 D, 20–22 E, 22–24 F, 24–26 G, 26–28 H",
        "variables": {
            "Underbust": "measured snugly just below the bust",
            "Bust": "measured loosely around the fullest part"
        }
    },
    "worked_example": {
        "inputs": {
            "unit": "cm",
            "underbust": "87",
            "bust": "107"
        },
        "steps": [
            "Band: 87 cm rounds to the nearest 5 cm, 85.",
            "Difference: 107 − 87 = 20 cm.",
            "20 cm falls in the over-18-to-20 cm range, cup D."
        ],
        "result": "An underbust of 87 cm and a bust of 107 cm give a European size of 85D."
    },
    "interpretation": "Treat the result as a starting size to try on. Fit varies by brand and style, and UK and US sizes use inch bands and different letters above D, so the same measurements can carry a different label there.",
    "assumptions": [
        "EN 13402 European size ranges, as tabulated by mobilefish.com.",
        "Measurements taken while wearing a non-padded bra or none, tape level all round."
    ],
    "limitations": [
        "UK and US sizes are not converted: their cup sequences differ between countries and brands.",
        "The table covers cups AA to H and bands 60 to 125."
    ],
    "rules": null,
    "faqs": [
        {
            "question": "Why does my size differ between shops?",
            "answer": "Brands cut differently and UK, US, French and Australian sizes use other band numbers and cup letters. Use your measurements and each brand’s chart."
        },
        {
            "question": "What if I am between two cups?",
            "answer": "The cup changes every 2 cm; if you are right on a boundary, try both sizes."
        }
    ],
    "sources": [
        {
            "title": "EN 13402 cup and band size table (mobilefish.com)",
            "url": "https://www.mobilefish.com/popupwindow/en13402_pictogram_help_all.php?help=cup"
        }
    ],
    "related": [
        {
            "name": "Length Converter",
            "url": "https://calculators.geekmidst.com/calculators/length-converter"
        },
        {
            "name": "Height Calculator",
            "url": "https://calculators.geekmidst.com/calculators/height-calculator"
        }
    ],
    "disclaimer": null,
    "publisher": "GM¹X CalcVerse"
}