Pediatric Dosing Calculator

Weight-based pediatric dosing with Lexicomp / Micromedex cross-check. Supports mg/kg, mcg/kg, and per-day or per-dose regimens.

Calculate pediatric doses using weight-based dosing, Clark's rule, or Young's rule.

kg
mg/kg

Formula

Dose = Weight (kg) × Dose per kg, divided by the prescribed frequency

Always check against age-band labeling and maximum dose. Use ideal body weight for obese pediatric patients. Clark's rule: child dose = (weight in lb ÷ 150) × adult dose.

Step-by-step method

  1. 1

    Find the FDA / Lexicomp pediatric entry

    Look up the drug in the FDA label or Lexicomp / Micromedex pediatric module and identify the dose for the child's age band and indication.

  2. 2

    Confirm the child's weight

    Use the most recent recorded weight in kg. Convert pounds → kg if needed (1 lb = 0.4536 kg).

  3. 3

    Multiply weight by dose per kg

    Dose per administration = Weight × Dose per kg.

  4. 4

    Apply the maximum cap

    Compare against the labeled maximum daily and per-dose limits — do not exceed adult dose.

  5. 5

    Round to a measurable volume

    Round to a volume that can be measured accurately with the supplied oral syringe.

Worked example

Scenario: Amoxicillin 25 mg/kg PO q8h for an 18 kg child.

Answer: 18 × 25 = 450 mg q8h; 1350 mg total daily.

Practice calculations for the NAPLEX

350+ exam-style calculation questions with detailed explanations, mapped to NABP NAPLEX competency Area 4 (Perform Calculations).

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