{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"body-surface-area"},"result":{"entity_type":"calculator","id":"body-surface-area","calculator_id":"body-surface-area","canonical_url":"https://tttkmbb.com/health/body-surface-area","name":"Body Surface Area Calculator","title":"Body Surface Area Calculator – Mosteller and Du Bois Formulas","category":"health","category_name":"Health","tool_name":"calculate_body_surface_area","featured_mcp_tool":false,"description":"Computes body surface area in square metres from height and weight using the Mosteller and Du Bois formulas, as used for chemotherapy and other weight-independent dosing.","use_when":"You need BSA for drug dosing, cardiac index or physiological normalisation.","do_not_use_when":"You need body composition or BMI; BSA does not indicate fatness.","inputs":[{"name":"weight_kg","label":"Weight","type":"number","unit":"kg","required":true,"max":700,"exclusive_min":0,"description":"Body weight in kilograms.","example":70},{"name":"height_cm","label":"Height","type":"number","unit":"cm","required":true,"min":30,"max":300,"description":"Height in centimetres.","example":175}],"outputs":[{"name":"bsa_mosteller_m2","label":"BSA (Mosteller)","type":"number","unit":"m²","decimals":3,"description":"√(height_cm × weight_kg / 3600)."},{"name":"bsa_dubois_m2","label":"BSA (Du Bois)","type":"number","unit":"m²","decimals":3,"description":"0.007184 × weight^0.425 × height^0.725."},{"name":"bsa_haycock_m2","label":"BSA (Haycock)","type":"number","unit":"m²","decimals":3,"description":"0.024265 × weight^0.5378 × height^0.3964 (often used in paediatrics)."}],"input_schema":{"type":"object","properties":{"weight_kg":{"description":"Body weight in kilograms. Unit: kg.","type":"number","maximum":700,"exclusiveMinimum":0,"examples":[70],"x-unit":"kg"},"height_cm":{"description":"Height in centimetres. Unit: cm.","type":"number","minimum":30,"maximum":300,"examples":[175],"x-unit":"cm"}},"additionalProperties":false,"required":["weight_kg","height_cm"]},"output_schema":{"type":"object","properties":{"bsa_mosteller_m2":{"description":"√(height_cm × weight_kg / 3600). Unit: m².","type":"number","x-unit":"m²"},"bsa_dubois_m2":{"description":"0.007184 × weight^0.425 × height^0.725. Unit: m².","type":"number","x-unit":"m²"},"bsa_haycock_m2":{"description":"0.024265 × weight^0.5378 × height^0.3964 (often used in paediatrics). Unit: m².","type":"number","x-unit":"m²"}}},"formula":"Mosteller: BSA = √(H·W / 3600). Du Bois: BSA = 0.007184 · W^0.425 · H^0.725. Haycock: BSA = 0.024265 · W^0.5378 · H^0.3964. H in cm, W in kg.","sources":[{"name":"Mosteller RD (1987) Simplified calculation of body-surface area, N Engl J Med 317:1098","url":"https://pubmed.ncbi.nlm.nih.gov/3657876/","type":"peer_reviewed","retrieved_at":"2026-09-23"},{"name":"Du Bois D, Du Bois EF (1916) A formula to estimate the approximate surface area if height and weight be known, Arch Intern Med 17:863-871","url":"https://pubmed.ncbi.nlm.nih.gov/2520314/","type":"peer_reviewed","retrieved_at":"2026-09-23"}],"freshness":{"type":"static","max_age_seconds":null,"note":"Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output."},"examples":[{"name":"70 kg, 175 cm","inputs":{"weight_kg":70,"height_cm":175},"expected":{"bsa_mosteller_m2":1.845,"bsa_dubois_m2":1.847,"bsa_haycock_m2":1.85},"url":"https://tttkmbb.com/api/v1/calculate/body-surface-area?weight_kg=70&height_cm=175"}],"faq":[{"q":"Which formula do hospitals use?","a":"Mosteller is the most common because it is simple and within 1–2% of Du Bois for adults; Haycock is favoured for infants and children."}],"tags":["body surface area","bsa","mosteller","du bois","chemotherapy dosing"],"related":[{"calculator_id":"bmi","reason":"A different height–weight index used for weight classification."}],"links":{"html":"https://tttkmbb.com/health/body-surface-area","markdown":"https://tttkmbb.com/health/body-surface-area.md","json":"https://tttkmbb.com/health/body-surface-area.json","api":"https://tttkmbb.com/api/v1/calculate/body-surface-area","schema":"https://tttkmbb.com/api/v1/calculators/body-surface-area","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-23"},"timestamp":"2026-09-23T23:31:32Z","next_actions":[{"tool":"run_calculator","calculator_id":"body-surface-area","reason":"Run Body Surface Area Calculator with the inputs above."}],"links":{"markdown":"https://tttkmbb.com/health/body-surface-area.md"}}