Calculate pediatric amoxicillin doses by weight, indication, and formulation. Includes suspension volume, dosing schedules, and indication-specific reference tables.
The Amoxicillin Pediatric Dosage Calculator provides weight-based dosing for one of the most commonly prescribed antibiotics in children. Amoxicillin, a broad-spectrum penicillin, is used to treat ear infections, strep throat, sinusitis, pneumonia, urinary tract infections, and skin infections in pediatric patients. The goal is to translate the prescribed mg/kg/day range into a practical dose volume without changing the underlying prescription.
Proper dosing in children requires precise weight-based calculations to ensure therapeutic drug levels while minimizing side effects. The standard dosing ranges from 25 mg/kg/day for mild infections up to 90 mg/kg/day for resistant organisms (such as penicillin-resistant Streptococcus pneumoniae in acute otitis media). The calculator converts these mg/kg doses into practical volume measurements (mL and teaspoons) based on the specific suspension concentration dispensed.
This tool also helps estimate the total medication volume needed for the treatment course, helping parents prepare and pharmacies dispense the correct quantity. While highly useful, dosing should always be confirmed by the prescribing pediatrician or pharmacist. Check the example with realistic values before reporting.
Incorrect antibiotic dosing in children is a common issue — under-dosing contributes to antibiotic resistance, while over-dosing increases side effect risk. Weight-based calculations are essential because children vary enormously in size, and fixed doses appropriate for one child may be dangerous or ineffective for another. This calculator bridges the gap between the physician prescription (mg/kg/day) and the practical measurement parents need (mL of suspension per dose), reducing medication errors.
Daily Dose = Weight (kg) × Dose Rate (mg/kg/day) Per-Dose Amount = Daily Dose ÷ Number of Doses/Day Volume per Dose (mL) = (Per-Dose mg ÷ Concentration mg) × 5 mL Total Course Volume = Volume per Dose × Doses/Day × Treatment Days
Result: 200 mg per dose (4 mL), three times daily
A 15 kg child with acute otitis media at standard dose (40 mg/kg/day) receives 600 mg/day. Divided into three doses: 200 mg each. Using 250 mg/5 mL suspension, each dose is 4 mL.
The rise of penicillin-resistant Streptococcus pneumoniae has shifted treatment paradigms in pediatrics. High-dose amoxicillin (80–90 mg/kg/day) achieves higher middle ear fluid concentrations that can overcome intermediate resistance. Risk factors for resistant organisms include age under 2, daycare attendance, recent antibiotic use (within 90 days), and geographic regions with high resistance rates.
The 125 mg/5 mL formulation is ideal for infants and small toddlers who need small volumes. The 250 mg/5 mL concentration is the most commonly dispensed for typical pediatric patients. The 400 mg/5 mL concentration is preferred for high-dose regimens in older or heavier children, as it reduces the volume per dose — improving palatability and adherence. Pharmacists may substitute concentrations based on availability.
Treatment duration varies by indication: acute otitis media in children under 2 typically requires 10 days, while children over 2 with mild disease may be treated for 5–7 days. Group A strep pharyngitis always requires a full 10-day course to prevent rheumatic fever. Sinusitis treatment ranges from 10–14 days. Shorter courses may be appropriate for uncomplicated UTIs. Always follow the prescriber's recommended duration.
Standard dose is 40–45 mg/kg/day divided into 3 doses, or 80–90 mg/kg/day divided BID for high-dose therapy when resistant organisms are suspected. Use this as a practical reminder before finalizing the result.
High-dose (80–90 mg/kg/day) is recommended when penicillin-resistant Streptococcus pneumoniae is suspected — common in daycare children, those with recent antibiotic use, or treatment failures. Keep this note short and outcome-focused for reuse.
Use the oral dosing syringe provided with the medication. Kitchen teaspoons are inaccurate and should not be used for pediatric medications, because they vary too much in size.
Yes. Once reconstituted, amoxicillin suspension should be refrigerated and used within 14 days. Shake well before each dose.
If vomiting occurs within 30 minutes, redose. If more than 30 minutes have passed, the dose was likely absorbed and should not be repeated.
Yes. Amoxicillin can be taken with or without food. Giving it with food may reduce stomach upset in sensitive children.