Flu treatment and prevention (prescription) · Prescription
Tamiflu (oseltamivir) dosage for children
Also sold as Tamiflu, oseltamivir suspension
Tamiflu is dosed by weight for children 1 year and older: 30 mg for 15 kg (33 lb) or less, 45 mg for over 15 to 23 kg, 60 mg for over 23 to 40 kg, and 75 mg over 40 kg. For treatment, give it twice a day for 5 days. For prevention, it’s given once a day: the CDC lists 7 days and the FDA label 10 days, so follow the length on your prescription. Babies under 1 year get 3 mg/kg per dose. The liquid is 6 mg per mL.
Source: Centers for Disease Control and Prevention · U.S. FDA label via DailyMed
Tamiflu dose calculator
Tamiflu dosage chart (1 year and older)
| Weight | Dose | Treatment | Prevention |
|---|---|---|---|
| 15 kg or less (33 lb or less) | 30 mg (5 mL) | Twice a day, 5 days | Once a day, 7-10 days* |
| Over 15 to 23 kg (33-51 lb) | 45 mg (7.5 mL) | Twice a day, 5 days | Once a day, 7-10 days* |
| Over 23 to 40 kg (51-88 lb) | 60 mg (10 mL) | Twice a day, 5 days | Once a day, 7-10 days* |
| Over 40 kg (88 lb) | 75 mg (12.5 mL) | Twice a day, 5 days | Once a day, 7-10 days* |
| Under 1 year (0-8 months) | 3 mg/kg | Twice a day, 5 days | Once a day, 7-10 days* (3 months and older) |
| Under 1 year (9-11 months) | 3.5 mg/kg | Twice a day, 5 days | 3 mg/kg once a day, 7-10 days* |
Doses: Centers for Disease Control and Prevention; the 3.5 mg/kg dose for 9-11 months is the AAP recommendation cited by the CDC. 6 mg/mL strength, capsule sizes and the 10-day prevention course: U.S. FDA label via DailyMed.
Start early
Tamiflu works best when started within 48 hours of flu symptoms, but doctors often still prescribe it later for young children, who are at higher risk of complications. Children under 5, and especially under 2, are in the higher-risk group.
Babies and preterm infants
For babies under 1 year, the dose is based on exact weight: 3 mg/kg per dose (the AAP recommends 3.5 mg/kg for babies 9 to 11 months). Preterm babies need a lower dose based on their age since conception. Their doctor will set it, and this calculator doesn’t cover them.
Prevention doses aren’t recommended for babies under 3 months unless a doctor decides the situation is critical.
Giving Tamiflu
- The pharmacy usually mixes the powder into a 6 mg/mL liquid. Check that your label says 6 mg/mL before using the mL amounts here.
- Give with food if it upsets your child’s stomach; nausea and vomiting are the most common side effects.
- Capsules (30, 45, 75 mg) can be opened and mixed with something sweet if your pharmacist says it’s OK.
Flu warning signs
- Trouble breathing, bluish lips, chest pain, or dehydration: call right away.
- Unusual behavior or confusion after starting the medicine.
- Flu symptoms improve and then return with fever and a worse cough.
- Your child has kidney disease; the dose may need adjusting.
Common questions
How much Tamiflu for a 2-year-old?
It depends on weight, not age. Most 2-year-olds weigh 15 kg (33 lb) or less and take 30 mg (5 mL of 6 mg/mL liquid) twice a day for 5 days.
Is 4 days of Tamiflu enough?
The standard treatment course is 5 days. Finish it unless your doctor says otherwise.
Can children take the 75 mg capsule?
Children over 40 kg (88 lb) take the adult dose of 75 mg. Younger children who can swallow capsules may use the 30 or 45 mg capsules that match their weight.
Sources
- Influenza Antiviral Medications: Summary for Clinicians. Centers for Disease Control and Prevention (reviewed 10 Mar 2026). Checked 2026-09-18.
- Tamiflu (oseltamivir phosphate) prescribing information: Dosage and Administration, Dosage Forms. U.S. FDA label via DailyMed (Genentech). Checked 2026-09-25.