What is amoxicillin, and what is it used for?
Amoxicillin is a type of antibiotic — a substance that kills bacteria or inhibits its further growth. It belongs to the penicillin group and is effective against a wide range of gram-positive and some gram-negative bacteria. Amoxicillin can be used in both inpatients and outpatients.
Amoxicillin is used worldwide and is one of the most frequently prescribed drugs in the United States, and the most popular antibiotic globally. It is commonly used to treat:
- Acute otitis media (ear infections) — one of the most common indications in children
- Streptococcal pharyngitis (strep throat)
- Community-acquired pneumonia (mild to moderate)
- Urinary tract infections (UTI)
- Skin and soft tissue infections
- Sinusitis (acute bacterial)
💡 Amoxicillin is often combined with clavulanic acid (Augmentin®) — a substance that enhances the bacteria-killing ability of this antibiotic. This way amoxicillin can be used for a wider range of pathogens that would otherwise be resistant.
How to use the amoxicillin pediatric dosage calculator?
- Select the indication — choose the condition being treated (e.g., ear infection, strep throat)
- Choose weight unit — kilograms (kg) for metric, pounds (lbs) for imperial
- Enter child's weight — the weight of the child in the selected unit
- Select the medication form — oral suspension, tablets, or chewable tablets
- Click Calculate to see the recommended dose range
The calculator shows:
- Daily dose range (minimum and maximum)
- Per-dose amount and dosing frequency
- Suspension dosing in ml for different concentrations (125, 200, 250, 400 mg/5 ml)
- Tablet dosing options (250 mg, 500 mg, 875 mg)
How to calculate amoxicillin dosage for pediatric patients?
Amoxicillin dosage for children is calculated based on the child's body weight in kg. The standard formula is:
Daily Dose (mg) = Weight (kg) × Dose per kg (mg/kg/day)
Dosage by indication (WHO & AAP guidelines)
| Indication | Dose (mg/kg/day) | Frequency | Max daily dose |
|---|---|---|---|
| Mild–Moderate infections | 25–45 mg/kg/day | 3× daily (TID) | 1,500 mg/day |
| Acute Otitis Media | 80–90 mg/kg/day | 2× daily (BID) | 3,000 mg/day |
| Strep Pharyngitis | 50 mg/kg/day | 2× daily (BID) | 1,000 mg/day |
| Community Pneumonia | 80–90 mg/kg/day | 2× daily (BID) | 3,000 mg/day |
| Urinary Tract Infection | 25–50 mg/kg/day | 3× daily (TID) | 1,500 mg/day |
Amoxicillin dosage charts by weight
Mild to Moderate Infections (25–45 mg/kg/day, TID)
| Weight (kg) | Weight (lbs) | Daily dose | Per dose (TID) | 125 mg/5 ml | 250 mg/5 ml |
|---|---|---|---|---|---|
| 5 | 11 | 125–225 mg | 42–75 mg | 1.7–3 ml | 0.8–1.5 ml |
| 10 | 22 | 250–450 mg | 83–150 mg | 3.3–6 ml | 1.7–3 ml |
| 15 | 33 | 375–675 mg | 125–225 mg | 5–9 ml | 2.5–4.5 ml |
| 20 | 44 | 500–900 mg | 167–300 mg | 6.7–12 ml | 3.3–6 ml |
| 25 | 55 | 625–1125 mg | 208–375 mg | 8.3–15 ml | 4.2–7.5 ml |
| 30 | 66 | 750–1350 mg | 250–450 mg | 10–18 ml | 5–9 ml |
High-Dose (80–90 mg/kg/day, BID — for Otitis Media & Pneumonia)
| Weight (kg) | Weight (lbs) | Daily dose | Per dose (BID) | 400 mg/5 ml | 500 mg tablet |
|---|---|---|---|---|---|
| 5 | 11 | 400–450 mg | 200–225 mg | 2.5–2.8 ml | 0.4–0.45 |
| 10 | 22 | 800–900 mg | 400–450 mg | 5–5.6 ml | 0.8–0.9 |
| 15 | 33 | 1200–1350 mg | 600–675 mg | 7.5–8.4 ml | 1.2–1.35 |
| 20 | 44 | 1600–1800 mg | 800–900 mg | 10–11.3 ml | 1.6–1.8 |
| 25 | 55 | 2000–2250 mg | 1000–1125 mg | 12.5–14.1 ml | 2–2.25 |
| 30+ | 66+ | 2400–3000 mg | 1200–1500 mg | 15–18.8 ml | 2.4–3 |
FAQs
What is the typical amoxicillin dose for a child?
For mild to moderate infections, the typical dose is 25–45 mg/kg/day divided into 3 doses. For serious infections like ear infections or pneumonia, higher doses of 80–90 mg/kg/day divided into 2 doses are used.
What is the maximum amoxicillin dose for children?
The maximum daily dose depends on the indication: 1,500 mg/day for mild infections and up to 3,000 mg/day for serious infections like acute otitis media and pneumonia. The adult dose cap (typically 3,000 mg/day) should not be exceeded.
How long should a child take amoxicillin?
The standard course is 10 days for most infections. For strep pharyngitis, 10 days is recommended to prevent rheumatic fever. Some guidelines allow 5–7 day courses for uncomplicated ear infections in older children (≥2 years).
What forms of amoxicillin are available for children?
Children can take amoxicillin as:
- Oral suspension — available in 125 mg/5 ml, 200 mg/5 ml, 250 mg/5 ml, 400 mg/5 ml
- Chewable tablets — 125 mg and 250 mg
- Capsules/tablets — 250 mg, 500 mg, 875 mg (for older children/adolescents)
Can amoxicillin cause side effects in children?
Common side effects include diarrhea, nausea, vomiting, and rash. Allergic reactions (including anaphylaxis) can occur — seek emergency help if the child develops hives, difficulty breathing, or swelling. Amoxicillin should not be used in children with known penicillin allergies.
⚠️ Medical Disclaimer: This calculator is for informational purposes only and cannot replace a real medical consultation. Always seek the advice of a qualified healthcare provider before giving any medication to a child. Dosages may vary based on local guidelines, specific formulations, and individual patient factors.