Weight-Based Dose Calculator
Calculate mg/kg bolus doses and mcg/kg/min infusion rates. Automatically converts lbs to kg. Built for EMT, AEMT, and paramedic exam prep.
Part of the EMS Medical Calculator Suite
Presets
Quick Weight Conversion Reference
Formula: kg = lbs ÷ 2.2 (NREMT standard). For pediatric weight estimation by age, see the Pediatric EMS Reference.
How Weight-Based Dosing Works in EMS
Many medications — especially those used in pediatric patients or advanced life support — are dosed based on the patient's weight. The ordered dose is expressed as an amount per kilogram (mg/kg or mcg/kg), and you must multiply that by the patient's weight to get the total dose to administer.
The NREMT expects you to perform this math without a calculator. The most common error is failing to convert pounds to kilograms first. Always divide pounds by 2.2 (or 2.2046 for precision) before applying a per-kg dose.
mcg/kg/min Drip Calculations Explained
Vasopressor and cardiac drips at the paramedic level (dopamine, epinephrine, norepinephrine) are ordered in micrograms per kilogram per minute. The pump is set in mL/hr. To convert:
The "× 60" converts per-minute rate to per-hour rate for the pump. For example: dopamine 5 mcg/kg/min for a 70 kg patient, concentration 1,600 mcg/mL: (5 × 70 × 60) ÷ 1,600 = 21,000 ÷ 1,600 = 13.1 mL/hr.
For IV flow rate and drip calculations, use the IV drip rate calculator.
Frequently Asked Questions
Why do I divide by 2.2 to convert lbs to kg?
One kilogram equals 2.2046 pounds. Dividing by 2.2 is the standard clinical approximation. For exam purposes, use 2.2 unless the question specifies otherwise. For a 154 lb patient: 154 ÷ 2.2 = 70 kg.
What's the pediatric weight estimation formula?
For children aged 1–10 years, EMS providers use the formula: Weight (kg) ≈ 2 × (age in years + 4). A 6-year-old child: 2 × (6 + 4) = 20 kg. The Broselow Tape uses color-coded zones to correlate patient length with estimated weight and pre-calculated drug doses. See the Pediatric EMS Reference for full tables.
What is mcg/kg/min and when is it used?
Micrograms per kilogram per minute (mcg/kg/min) is the dosing unit for continuous IV infusions of potent drugs like dopamine, epinephrine, and norepinephrine. These drips are titrated in real time to patient response, so both the ordered dose and pump rate need to be verified continuously. Most ALS protocols allow paramedics to initiate these infusions in cardiogenic shock, septic shock, and post-resuscitation care.
How do I calculate medication dosage for pediatric patients?
The process is identical to adult weight-based dosing, but always use or estimate weight in kilograms first (Broselow, parental estimate, or scale weight). Then apply the per-kg dose. Important: many pediatric doses have maximum caps — for example, the first dose of adenosine is 0.1 mg/kg, maximum 6 mg regardless of weight. Always apply max dose limits from your protocols.
Frequently Asked Questions
- How do I convert lbs to kg for EMS dosing?
- Divide pounds by 2.2 to get kilograms. For a 154 lb patient: 154 ÷ 2.2 = 70 kg. On the NREMT, this conversion is often a required step before a dosage calculation — always convert first.
- What is the mcg/kg/min infusion formula?
- mL/hr = (Dose in mcg/kg/min × Weight in kg × 60) ÷ Concentration in mcg/mL. The × 60 converts per-minute to per-hour for the pump. Example: dopamine 5 mcg/kg/min, 70 kg patient, 1,600 mcg/mL: (5 × 70 × 60) ÷ 1,600 = 13.1 mL/hr.
- How do I estimate pediatric weight without a scale?
- Use the Broselow Tape in the field — it estimates weight from patient length and provides color-coded drug doses. For written exam problems, use the formula: kg ≈ 2 × (age in years + 4) for children aged 1–10 years.
- How do I calculate a dopamine drip rate step by step?
- Step 1: Convert weight to kg (lbs ÷ 2.2). Step 2: Multiply dose (mcg/kg/min) × weight (kg) × 60 to get mcg/hr. Step 3: Divide by the concentration in mcg/mL to get mL/hr. Example: 5 mcg/kg/min, 70 kg patient, 400 mg dopamine in 250 mL (= 1,600 mcg/mL): (5 × 70 × 60) ÷ 1,600 = 13.1 mL/hr.
- What is the lbs to kg conversion formula?
- Divide pounds by 2.2 (precise value: 2.2046). Quick reference: 110 lbs = 50 kg, 132 lbs = 60 kg, 154 lbs = 70 kg, 176 lbs = 80 kg, 198 lbs = 90 kg, 220 lbs = 100 kg. On NREMT exams, dividing by 2.2 is the accepted method unless otherwise specified.
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