Dosage Calculator

Calculate medication dosage and volume. Enter patient weight, dose, and concentration. Get total dose in mg/mL, volume to administer, and tablet count. Informational only—consult a healthcare professional.

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Published: October 23, 2025 | Updated: October 23, 2025 | Reviewed by: Medical/Health Editor

Patient Information

Enter patient's current weight

Dosage Information

Prescribed dose per kg/m²

Medication Form

Medication concentration in mg per mL

Preset Patients

Export/Import

How it works

Total Dose = Weight (kg) × Dose (mg/kg). Volume = Total Dose / Concentration. We calculate the total dose based on weight and then determine the volume or number of tablets needed.

The calculator supports different dosage types and medication forms to accommodate various prescriptions.

Inputs explained

  • Patient Weight: The patient's current body weight in kg or lbs.
  • Dosage Type: The unit of measurement for the prescription (mg/kg, mcg/kg, mg/m², or IU/kg).
  • Dose Amount: The prescribed amount per unit of weight or surface area.
  • Medication Form: Whether the medication is liquid, tablets/capsules, or injection.
  • Concentration: For liquids, the strength of the medication in mg per mL.
  • Tablet Strength: For tablets/capsules, the amount of medication per unit.

Example

Scenario: Adult patient, 70 kg, prescribed 5 mg/kg of liquid medication with concentration 10 mg/mL

Calculation:

  • Total Dose = 70 kg × 5 mg/kg = 350 mg
  • Volume = 350 mg ÷ 10 mg/mL = 35 mL

Result: Administer 35 mL of the liquid medication

Tips & notes

  • Always use a calibrated measuring device (syringe or cup) for liquid medications
  • Double-check the units (mg, mcg, mL) to avoid potentially dangerous errors
  • Follow the prescription exactly as written by the doctor
  • Never split or crush tablets unless specifically instructed
  • For pediatric patients, verify all calculations with a pharmacist
  • Store medications as directed and check expiration dates
  • 1 mg = 1000 mcg; 1 g = 1000 mg (know your conversions)

FAQs

Multiply the patient's weight by the prescribed dose per kg. For example, for a 70 kg patient with a dose of 5 mg/kg: 70 × 5 = 350 mg.

Milligrams per kilogram, a common unit for pediatric dosages. It expresses the medication dose relative to body weight to ensure appropriate dosing for patients of different sizes.

Divide the total dose in mg by the concentration in mg/mL. For example, 350 mg ÷ 10 mg/mL = 35 mL.

Only split tablets if they are scored (have a line down the middle) and your doctor approves. Otherwise, ask your pharmacist about alternative formulations.

1 mg (milligram) = 1000 mcg (micrograms). Confusing these units is a common and potentially dangerous medication error.

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Disclaimer

Informational tool based on standard dosage calculations. Not a substitute for professional medical advice. Always follow the prescription and consult a doctor or pharmacist. Medication errors can be life-threatening. When in doubt, seek professional guidance.

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