{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"dose-by-weight"},"result":{"entity_type":"calculator","id":"dose-by-weight","calculator_id":"dose-by-weight","canonical_url":"https://tttkmbb.com/medical/dose-by-weight","name":"Dose by Weight Calculator","title":"Weight-Based Dose Calculator – mg/kg per Dose or per Day to mg and mL per Administration","category":"medical","category_name":"Medical & Clinical","tool_name":"calculate_dose_by_weight","featured_mcp_tool":false,"description":"Converts a weight-based dose (mg/kg per dose or per day) into milligrams per administration and per day, the volume per administration for a given concentration, and applies an optional maximum single dose.","use_when":"A drug reference gives a dose in mg/kg and you know the patient's weight, the dosing frequency and, optionally, the product concentration or a maximum dose.","do_not_use_when":"The dose is based on body surface area (use body-surface-area), units are not mg/kg (e.g. mcg/kg/min infusions), or renal or hepatic adjustment is required; drug-specific references govern the actual prescription.","inputs":[{"name":"dose_mg_per_kg","label":"Dose","type":"number","unit":"mg/kg","required":true,"max":1000,"exclusive_min":0,"description":"Dose in mg per kg, per administration or per day as set by dose_basis.","example":10},{"name":"weight_kg","label":"Weight","type":"number","unit":"kg","required":true,"max":700,"exclusive_min":0,"description":"Patient weight in kilograms (the dosing weight, e.g. actual or adjusted).","example":20},{"name":"dose_basis","label":"Dose basis","type":"enum","required":false,"default":"per_dose","values":[{"value":"per_dose","label":"mg/kg per dose","aliases":["dose","per_administration"]},{"value":"per_day","label":"mg/kg per day (divided)","aliases":["day","daily"]}],"description":"Whether dose_mg_per_kg is per administration or the total for the day.","example":"per_dose"},{"name":"doses_per_day","label":"Doses per day","type":"integer","required":false,"default":1,"min":1,"max":24,"description":"Number of administrations in 24 hours (e.g. 3 for every 8 hours).","example":3},{"name":"concentration_mg_per_ml","label":"Concentration","type":"number","unit":"mg/mL","required":false,"max":10000,"exclusive_min":0,"description":"Optional product concentration (e.g. 250 mg/5 mL = 50 mg/mL) to obtain the volume.","example":50},{"name":"max_dose_mg","label":"Maximum single dose","type":"number","unit":"mg","required":false,"max":100000,"exclusive_min":0,"description":"Optional cap per administration (often the adult dose); the calculated dose is limited to it.","example":500}],"outputs":[{"name":"dose_per_administration_mg","label":"Dose per administration","type":"number","unit":"mg","decimals":2,"description":"Milligrams per dose (after any cap)."},{"name":"daily_total_mg","label":"Daily total","type":"number","unit":"mg/day","decimals":2,"description":"Dose per administration × doses per day."},{"name":"volume_per_administration_ml","label":"Volume per administration","type":"number","unit":"mL","decimals":2,"description":"Dose / concentration; only when concentration_mg_per_ml is given."},{"name":"daily_volume_ml","label":"Daily volume","type":"number","unit":"mL/day","decimals":2,"description":"Only when concentration_mg_per_ml is given."},{"name":"dosing_interval_hours","label":"Dosing interval","type":"number","unit":"h","decimals":1,"description":"24 / doses per day."},{"name":"dose_capped","label":"Capped at maximum","type":"boolean","decimals":4,"description":"True when the weight-based dose exceeded max_dose_mg and was limited."}],"input_schema":{"type":"object","properties":{"dose_mg_per_kg":{"description":"Dose in mg per kg, per administration or per day as set by dose_basis. 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Results are informational only and not a substitute for clinical judgement or medical advice.","sources":[{"name":"Craker M, Janke C (2024) Nursing Dosage Calculations (open textbook, WisTech Open)","url":"https://wtcs.pressbooks.pub/nursingdosagecalculations/","type":"textbook","retrieved_at":"2026-09-24"},{"name":"WHO – Promoting safety of medicines for children (2007)","url":"https://www.who.int/publications/i/item/9789241563437","type":"standard","retrieved_at":"2026-09-24"}],"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":"10 mg/kg per dose, 20 kg, 3 times daily, 50 mg/mL","inputs":{"dose_mg_per_kg":10,"weight_kg":20,"dose_basis":"per_dose","doses_per_day":3,"concentration_mg_per_ml":50},"expected":{"dose_per_administration_mg":200,"daily_total_mg":600,"volume_per_administration_ml":4,"daily_volume_ml":12,"dosing_interval_hours":8,"dose_capped":false},"url":"https://tttkmbb.com/api/v1/calculate/dose-by-weight?dose_mg_per_kg=10&weight_kg=20&dose_basis=per_dose&doses_per_day=3&concentration_mg_per_ml=50"},{"name":"30 mg/kg/day divided in 2, 15 kg","inputs":{"dose_mg_per_kg":30,"weight_kg":15,"dose_basis":"per_day","doses_per_day":2},"expected":{"dose_per_administration_mg":225,"daily_total_mg":450,"dosing_interval_hours":12},"url":"https://tttkmbb.com/api/v1/calculate/dose-by-weight?dose_mg_per_kg=30&weight_kg=15&dose_basis=per_day&doses_per_day=2"},{"name":"15 mg/kg per dose, 60 kg, cap 500 mg","inputs":{"dose_mg_per_kg":15,"weight_kg":60,"max_dose_mg":500},"expected":{"dose_per_administration_mg":500,"dose_capped":true},"url":"https://tttkmbb.com/api/v1/calculate/dose-by-weight?dose_mg_per_kg=15&weight_kg=60&max_dose_mg=500"}],"faq":[{"q":"Is 'mg/kg/day' the same as 'mg/kg per dose'?","a":"No. A daily dose is divided by the number of administrations; entering a per-day dose as per-dose would overdose by the frequency factor, which is why dose_basis is explicit."},{"q":"How do I get mg/mL from a label like 250 mg/5 mL?","a":"Divide: 250 / 5 = 50 mg/mL. For percentage solutions, 1% = 10 mg/mL."}],"tags":["dose by weight","mg/kg calculator","pediatric dose","weight based dosing","mg to ml"],"related":[{"calculator_id":"adjusted-body-weight","reason":"Choose the dosing weight for overweight patients."},{"calculator_id":"body-surface-area","reason":"BSA-based dosing alternative."},{"calculator_id":"iv-drip-rate","reason":"Set the infusion rate for the calculated volume."}],"links":{"html":"https://tttkmbb.com/medical/dose-by-weight","markdown":"https://tttkmbb.com/medical/dose-by-weight.md","json":"https://tttkmbb.com/medical/dose-by-weight.json","api":"https://tttkmbb.com/api/v1/calculate/dose-by-weight","schema":"https://tttkmbb.com/api/v1/calculators/dose-by-weight","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-24"},"timestamp":"2026-09-24T01:48:55Z","next_actions":[{"tool":"run_calculator","calculator_id":"dose-by-weight","reason":"Run Dose by Weight Calculator with the inputs above."}],"links":{"markdown":"https://tttkmbb.com/medical/dose-by-weight.md"}}