Pediatric and weight-based dosing is a high-priority NCLEX skill because a child’s dose depends entirely on accurate weight conversion and mg/kg math.
This free timed quiz includes 10 pediatric dosage calculation practice questions with answers and rationales, covering lb-to-kg conversion, mg/kg/day and mg/kg/dose orders, safe-dose range checks, and liquid suspension volumes.
Remember the two key steps: convert pounds to kilograms (lb ÷ 2.2 = kg), then multiply by the ordered mg/kg. Work each on paper, then check your answer.
All 10 Questions With Answers & Rationales
Prefer to work at your own pace? Every question from the timed quiz above is listed here in full. Solve each on paper, then tap Show Answer & Rationale to check your work.
Question 1: Weight-Based
A provider orders 15 mg/kg/day of an antibiotic for a child weighing 22 lb, divided into 2 equal doses. How many mg should the child receive per dose? (1 kg = 2.2 lb)
- A. 75 mg
- B. 150 mg
- C. 300 mg
- D. 37.5 mg
Show Answer & Rationale
Answer: A. 75 mg
Rationale: Convert weight: 22 lb ÷ 2.2 = 10 kg. Daily dose = 15 mg/kg × 10 kg = 150 mg/day. Divided into 2 doses = 150 ÷ 2 = 75 mg per dose.
Question 2: Safe Dose
A child weighs 18 kg. The safe range for a drug is 5-10 mg/kg/day. The provider orders 120 mg/day. Is this dose safe?
- A. Safe — it is within range
- B. Unsafe — it is too high
- C. Unsafe — it is too low
- D. Cannot be determined
Show Answer & Rationale
Answer: A. Safe — it is within range
Rationale: Safe range = 5 mg/kg × 18 kg = 90 mg/day (low) to 10 mg/kg × 18 kg = 180 mg/day (high). The ordered 120 mg/day falls between 90 and 180 mg, so it is safe.
Question 3: Weight-Based
A child weighs 44 lb. The order is 20 mg/kg/dose. How many mg should the nurse give per dose? (1 kg = 2.2 lb)
- A. 200 mg
- B. 400 mg
- C. 880 mg
- D. 100 mg
Show Answer & Rationale
Answer: B. 400 mg
Rationale: Convert: 44 lb ÷ 2.2 = 20 kg. Dose = 20 mg/kg × 20 kg = 400 mg per dose.
Question 4: Liquid Dose
A child is ordered 250 mg of amoxicillin. The suspension is labeled 125 mg/5 mL. How many mL should the nurse administer?
- A. 5 mL
- B. 10 mL
- C. 2.5 mL
- D. 12.5 mL
Show Answer & Rationale
Answer: B. 10 mL
Rationale: Use desired ÷ have × quantity: (250 mg ÷ 125 mg) × 5 mL = 2 × 5 = 10 mL.
Question 5: Weight-Based
An infant weighs 6.8 kg. The order is 2 mg/kg/dose. How many mg should the nurse give? (round to the nearest tenth)
- A. 13.6 mg
- B. 6.8 mg
- C. 3.4 mg
- D. 14 mg
Show Answer & Rationale
Answer: A. 13.6 mg
Rationale: Dose = 2 mg/kg × 6.8 kg = 13.6 mg.
Question 6: Daily Dose
A child weighing 25 kg is ordered 8 mg/kg/day divided every 8 hours. How many mg is each dose?
- A. 200 mg
- B. 66.7 mg
- C. 100 mg
- D. 50 mg
Show Answer & Rationale
Answer: B. 66.7 mg
Rationale: Daily dose = 8 mg/kg × 25 kg = 200 mg/day. Every 8 hours = 3 doses/day. 200 ÷ 3 = 66.7 mg per dose.
Question 7: Liquid Dose
A child needs 180 mg of a medication available as 200 mg/5 mL. How many mL should the nurse give? (round to the nearest tenth)
- A. 4.5 mL
- B. 5 mL
- C. 3.6 mL
- D. 9 mL
Show Answer & Rationale
Answer: A. 4.5 mL
Rationale: (180 mg ÷ 200 mg) × 5 mL = 0.9 × 5 = 4.5 mL.
Question 8: Safe Dose
A 12 kg child is ordered 300 mg/day of a drug with a safe maximum of 20 mg/kg/day. Is the dose within the safe maximum?
- A. Yes — under the maximum
- B. No — over the maximum
- C. Exactly at the maximum
- D. Cannot be determined
Show Answer & Rationale
Answer: B. No — over the maximum
Rationale: Safe maximum = 20 mg/kg × 12 kg = 240 mg/day. The ordered 300 mg/day exceeds 240 mg/day, so it is over the safe maximum and should be questioned.
Question 9: Weight-Based
A neonate weighs 3,200 g. The order is 4 mg/kg/dose. How many mg should the nurse administer? (1,000 g = 1 kg)
- A. 12.8 mg
- B. 1.28 mg
- C. 128 mg
- D. 3.2 mg
Show Answer & Rationale
Answer: A. 12.8 mg
Rationale: Convert grams to kg: 3,200 g ÷ 1,000 = 3.2 kg. Dose = 4 mg/kg × 3.2 kg = 12.8 mg.
Question 10: Liquid Dose
A child is prescribed 75 mg of a medication supplied as 25 mg/mL. How many mL should the nurse draw up?
- A. 1 mL
- B. 3 mL
- C. 2 mL
- D. 0.3 mL
Show Answer & Rationale
Answer: B. 3 mL
Rationale: (75 mg ÷ 25 mg) × 1 mL = 3 mL.
NCLEX Dosage Calculation Practice Tests
Master the medication math that shows up most on the NCLEX with 135 free, timed dosage questions — complete with answers and step-by-step rationales. Work through all twelve tests to build speed and confidence.
Dosage Calculations Practice Questions
Our original 25-item mixed practice set covering the core dosage calculations every nursing student needs to know.
IV Flow Rates
Drops per minute, mL/hr pump settings, and drop-factor calculations for IV infusions.
Pediatric & Weight-Based Dosing
mg/kg calculations, safe-dose range checks, and body-weight dosing for pediatric clients.
Heparin, Insulin & Units
High-alert unit-based math — heparin drips, insulin dosing, and weight-based bolus calculations.
Oral Meds & Unit Conversions
Tablets, oral suspensions, and metric conversions including g, mg, mcg, tsp, mL, and lb-to-kg.
Basic Dosage & Conversions
Tablets, oral liquids, and metric/household unit conversions — the foundation of safe medication math.
IV Titration (mcg/kg/min, mg/hr)
Vasoactive and sedation drips: mcg/kg/min, mcg/min and mg/hr to mL/hr, working back from the pump, and titration steps.
Reconstitution
Mixing powdered medications: diluent volume vs. final concentration, multi-strength vial tables, labeling, and doses per vial.
Safe-Dose Range
Is the prescribed dose safe? mg/kg/day vs. mg/kg/dose ranges, maximum-dose caps, unit conversions, and what to do when a dose is too high or too low.
IV Drip Rates & Infusion Times
When will the bag finish? Infusion end times, time left in a bag, counting drops on a gravity line, shift and 24-hour IV totals, and IVs that fall behind.
Pediatric BSA & Weight-Based Dosing
Body surface area with the Mosteller formula, mg/m² doses, BSA safe-dose checks, mL/kg boluses, maintenance fluid rates, and mg/kg/hr infusions for children.
Mixed Review
Every skill in the series mixed together: IM doses, heparin and insulin drips, lb-to-kg, mEq, percent solutions, g/hr infusions, pediatric liquids, gravity drips, and safe dose writing.
