Drug Calculations

Weight-Based Dose (mg/kg) Calculator

Turns an ordered mg/kg dose into the total dose, and into mL when you know the concentration.

Reviewed by Alex G, BSN, RN, CEN, CCRN, CMC, NREMT-P · From the Reference tab of the app

Turn on JavaScript to use this calculator, or open it in the web app.

Formula

Dose (mg) = mg/kg × weight (kg)
Volume (mL) = dose (mg) ÷ concentration (mg/mL)

How it is used

• Weigh the patient in kilograms. Pounds ÷ 2.2 = kilograms; using a pound value as kilograms more than doubles the dose.
• For children without a known weight, use a length-based resuscitation tape.
• Check the concentration on the vial every time: epinephrine comes as 1 mg/mL and 0.1 mg/mL, and the wrong one is a tenfold error.

Key points

• Say the drug, dose, concentration and volume aloud and have a partner confirm before giving a high-alert medication.

Same formula as the app. Open it in the web app.

Related one-pagers

• ACLS Algorithms in BriefLidocaine · 1–1.5 mg/kg, then 0.5–0.75 mg/kg
• Sedation, Pain and Delirium ScalesPropofol · Hypotension, high triglycerides; PRIS risk >5 mg/kg/h for >48 h; no analgesia
• CEN Pediatric Emergencies: Ingestions, GI, Head Injury and FracturesCannabis edible · Drowsiness, ataxia, bradypnea; THC over 5 mg/kg under age 5 linked to respiratory depression · Continuous SpO2 and respiratory monitoring, airway ready; supportive
• Neuro: ICP and StrokeTenecteplase · 0–4.5 h · 0.25 mg/kg IV push, max 25 mg

Drip cards with a dose ↔ mL/h converter

Related calculators

• Desired Over Have
• Drip Rate (drops/min)
• Half-Life
• Loading Dose
• Maintenance Dose
• mcg/kg/min to mL/hr
• Push-Dose Epinephrine
• Tablets or Capsules to Give

For education and exam preparation only. Follow your institution’s protocols. For education and exam preparation only. Verify results independently and follow your institution’s protocols. Not a substitute for clinical judgment.