Weight-Based Dose Calculator

Convert pounds to kilograms, multiply by mg/kg for the total dose, then divide by mg/mL. An optional per-dose split and each arithmetic step are shown.

For nurses, LPNs, pharmacy technicians, pharmacy technician students, and medical students. Convert pounds to kilograms, multiply by the ordered mg/kg, then divide the total milligrams by the concentration in mg/mL.

Follow facility protocol and the order on the medication administration record. This page shows arithmetic only. It does not choose a rate, a dose, or a product. A nurse or pharmacist confirms the result before anything is given.

Weight-based dose formula

  1. Enter weight in pounds or kilograms.
  2. Enter the ordered mg per kg.
  3. Enter the concentration in mg per mL.
  4. Optional: enter how many doses are given in the day.
  5. Read total milligrams, total milliliters, and the per-dose split when you asked for one.

Worked example: 154 lb, 5 mg/kg, 50 mg/mL

  1. These numbers are practice inputs, not an order to give.
  2. Kilograms = 154 ÷ 2.2 = 70. This calculator uses 2.2 pounds per kilogram.
  3. Total dose = 5 mg/kg × 70 kg = 350 mg.
  4. Volume = 350 mg ÷ 50 mg/mL = 7 mL.
  5. Optional split, 4 doses in the day: 350 ÷ 4 = 87.5 mg per dose, and 7 ÷ 4 = 1.75 mL per dose.

Kilograms = pounds ÷ 2.2 on this calculator. Total milligrams = mg/kg × kilograms. Milliliters = total milligrams ÷ the labeled mg/mL. An optional doses-per-day field splits both totals into equal doses. Leave that field blank when you only need the daily amount. This page is for nurses, LPNs, pharmacy technicians, pharmacy technician students, and medical students. It does not choose a dose, a concentration, or a schedule.

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Frequently asked questions

How do you convert pounds to kilograms here?

Divide pounds by 2.2. That is the conversion this calculator uses. If your facility uses a different pounds-per-kilogram factor, use that factor instead of this result.

How do you get milliliters from mg/kg?

Multiply mg/kg by the patient weight in kilograms to get total milligrams. Divide that total by the concentration in mg/mL to get milliliters.

What does the optional doses-per-day field do?

It divides the total milligrams and the total milliliters by the number of doses in the day. Leave it blank when you only need the full daily amount.

Who is this weight-based dose calculator for?

Nurses, LPNs, pharmacy technicians, pharmacy technician students, and medical students who need to see each conversion. It does not choose a dose.