{
    "name": "Body Surface Area Calculator",
    "url": "https://calculators.geekmidst.com/calculators/body-surface-area-calculator",
    "markdown": "https://calculators.geekmidst.com/calculators/body-surface-area-calculator.md",
    "category": "Health & fitness",
    "description": "Calculate body surface area in square metres from height and weight with the Mosteller, DuBois, Haycock and Gehan–George formulas side by side.",
    "summary": "Body surface area (BSA) is estimated from height and weight. Several published formulas exist; they usually agree within a few per cent for adults. This supports, and does not replace, clinical judgement.",
    "also_called": [
        "BSA 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": "units",
            "label": "Units",
            "type": "segmented",
            "default": "metric",
            "options": {
                "metric": "Metric (cm, kg)",
                "us": "US (ft, in, lb)"
            }
        },
        {
            "name": "height_cm",
            "label": "Height",
            "type": "number",
            "default": "170",
            "unit": "cm",
            "shown_when": {
                "units": "metric"
            }
        },
        {
            "name": "height_ft",
            "label": "Height (feet)",
            "type": "number",
            "default": "5",
            "unit": "ft",
            "shown_when": {
                "units": "us"
            }
        },
        {
            "name": "height_in",
            "label": "Height (inches)",
            "type": "number",
            "default": "9",
            "unit": "in",
            "optional": true,
            "shown_when": {
                "units": "us"
            }
        },
        {
            "name": "weight_kg",
            "label": "Weight",
            "type": "number",
            "default": "70",
            "unit": "kg",
            "shown_when": {
                "units": "metric"
            }
        },
        {
            "name": "weight_lb",
            "label": "Weight",
            "type": "number",
            "default": "154",
            "unit": "lb",
            "shown_when": {
                "units": "us"
            }
        }
    ],
    "outputs": [
        {
            "key": "mosteller",
            "label": "BSA (Mosteller)",
            "format": "number"
        },
        {
            "key": "dubois",
            "label": "BSA (DuBois & DuBois)",
            "format": "number"
        },
        {
            "key": "haycock",
            "label": "BSA (Haycock)",
            "format": "number"
        },
        {
            "key": "gehan_george",
            "label": "BSA (Gehan & George)",
            "format": "number"
        }
    ],
    "formula": {
        "text": "Mosteller: √(H × W ÷ 3600);  DuBois: 0.007184 × W^0.425 × H^0.725;  Haycock: 0.024265 × W^0.5378 × H^0.3964;  Gehan–George: 0.0235 × W^0.51456 × H^0.42246",
        "variables": {
            "H": "height in cm (1 in = 2.54 cm)",
            "W": "weight in kg (1 lb = 0.45359237 kg)"
        }
    },
    "worked_example": {
        "inputs": {
            "units": "metric",
            "height_cm": "180",
            "height_ft": "5",
            "height_in": "9",
            "weight_kg": "80",
            "weight_lb": "154"
        },
        "steps": [
            "Mosteller: √(180 × 80 ÷ 3600) = √4 = 2.00 m².",
            "DuBois: 0.007184 × 80^0.425 × 180^0.725 = 0.007184 × 6.43 × 43.2 ≈ 2.00 m²."
        ],
        "result": "A person 180 cm tall weighing 80 kg has a body surface area of about 2.0 m² by both Mosteller and DuBois."
    },
    "interpretation": "Typical adult values are roughly 1.6–2.0 m². BSA is used to index measurements such as cardiac output (cardiac index) and kidney function, and in some dosing protocols, where the prescriber chooses the formula.",
    "assumptions": [
        "Height and weight are measured, not estimated.",
        "Formulas were derived largely in adults (Haycock includes infants and children)."
    ],
    "limitations": [
        "Formulas diverge at extremes of body size, particularly severe obesity and very small children.",
        "Not a dosing tool: medicine doses must come from the prescriber, the product label or local protocol."
    ],
    "rules": null,
    "faqs": [
        {
            "question": "Which formula is best?",
            "answer": "Mosteller is simple and widely used; DuBois is the oldest and still common in physiology. For most adults the difference is a few hundredths of a square metre. Follow the formula your protocol specifies."
        },
        {
            "question": "Why is GFR reported per 1.73 m²?",
            "answer": "1.73 m² was the average adult BSA when the convention was set, so indexing to it lets kidney function be compared between people of different sizes."
        }
    ],
    "sources": [],
    "related": [
        {
            "name": "GFR Calculator",
            "url": "https://calculators.geekmidst.com/calculators/gfr-calculator"
        },
        {
            "name": "BMI Calculator",
            "url": "https://calculators.geekmidst.com/calculators/bmi-calculator"
        },
        {
            "name": "Body Type Calculator",
            "url": "https://calculators.geekmidst.com/calculators/body-type-calculator"
        }
    ],
    "disclaimer": "This is a general screening estimate for adults, not medical advice or a diagnosis. Talk to a qualified health professional about your health.",
    "publisher": "GM¹X CalcVerse"
}