For children aged 6 months and older, the standard single dose of ibuprofen is 10 mg per kilogram (mg/kg) of body weight, given every 6 to 8 hours as needed for fever or pain. The maximum daily dose is 40 mg/kg over 24 hours, capped at the adult ceiling for older children. The calculator applies this formula to the weight you enter and rounds the result to the nearest measurable amount for the product strength you select.
Ibuprofen Dosage by Weight Calculator
Weight-based Motrin® / Advil® dosing for infants, children, and adults with all common formulations.
Patient details
Draw to here
Children’s liquid- Frequency
- Every 6–8 h
- Max doses / day
- 4
- Daily max
- —
- Sanity check (mg/kg)
- —
Why the formulation matters — same volume, very different dose
5 mL of the two liquid ibuprofen products contain different amounts of drug. Always re-read the strength on the bottle before measuring.
| Weight | Single dose | Infant drops 50 mg / 1.25 mL | Children’s liquid 100 mg / 5 mL | Chewable 100 mg |
|---|
Highlighted row = closest match to the weight you entered.
Measuring a liquid dose accurately
- Use the oral syringe or dosing cup that came with the bottle. Household teaspoons are not measuring devices.
- Read the strength on the bottle each time — brand-name and store-brand bottles can look very similar but contain different concentrations.
- Shake the bottle for at least 10 seconds before each dose.
- Give with a small amount of food or milk if it upsets the stomach.
Chewable or swallowable tablets
- Chewable 100 mg tablets are typically used from age 6 years upward (or as advised by a clinician).
- Standard adult OTC tablets contain 200 mg per tablet.
- Take with a full glass of water; do not crush extended-release products (they are not used at OTC doses).
Spacing doses
- Minimum interval between doses: 6 hours (8 h preferred when symptoms are controlled).
- Maximum: 4 doses in any 24-hour window.
- Do not exceed 3 days of treatment for fever, or 10 days for pain, without consulting a clinician.
Do not use ibuprofen if…
- Infant under 6 months old, unless explicitly directed by a pediatrician (not FDA-approved in this group).
- Child weighs less than 12 lb / 5.5 kg, unless under medical supervision.
- Known allergy to ibuprofen, aspirin, or another NSAID; history of NSAID-induced asthma, urticaria, or angio-oedema.
- Active gastrointestinal bleeding, peptic ulcer, or known bleeding disorder.
- Significant kidney impairment, severe dehydration, vomiting, or persistent diarrhoea.
- Third trimester of pregnancy (FDA contraindication).
- Currently taking another NSAID, anticoagulant, or any combination cold/flu remedy that already contains ibuprofen.
Call your doctor immediately if
- Fever lasts more than 3 days in a child, or any fever ≥ 100.4°F (38.0°C) in an infant under 3 months.
- Vomiting after every dose, severe abdominal pain, dark or bloody stool, or blood in vomit.
- Signs of dehydration: very dry mouth, no wet diaper for 8+ hours, sunken eyes, lethargy.
- Suspected overdose — call Poison Control (US: 1-800-222-1222) immediately.
Primary references used
- American Academy of Pediatrics — Ibuprofen Dosing Table for Fever and PainHealthyChildren.org, AAP Council on Quality Improvement and Patient Safety.
- MedlinePlus (US National Library of Medicine) — Ibuprofen dosing for childrenPatient instructions, NIH MedlinePlus encyclopedia.
- DailyMed — Children’s Ibuprofen Oral Suspension USP 100 mg/5 mLCurrent FDA-cleared OTC consumer label, US National Library of Medicine.
- FDA — MOTRIN® Suspension Prescribing Information (PDF)US Food and Drug Administration, Drugs@FDA.
- Drugs.com — Ibuprofen Dosage Guide (max dose, adjustments)Compiled from US prescribing information; cross-reference only.
Reporting an error or adverse event
Suspected medication errors or adverse reactions to over-the-counter or prescription ibuprofen can be reported to the FDA’s MedWatch program or, in Europe, to your national pharmacovigilance authority via the EMA.
Full disclaimer, methodology, and how to report errors
What this tool is. An educational decision aid for weight-based ibuprofen dosing based on current US prescribing information (Motrin® Suspension label, DailyMed) and the American Academy of Pediatrics dosing tables. It is intended to help caregivers and clinicians cross-check a dose — not to prescribe.
What it is not. Not a substitute for a clinician’s evaluation, not a pharmacy dispensing system, and not validated for use outside the US (other regions may use different concentrations and unit conventions). Doses are rounded to the nearest measurable amount for the selected product; do not extrapolate beyond the formulations listed.
Calculation logic. Single dose = mg/kg target × weight in kg, capped at the single-dose ceiling for the selected formulation. Daily max = 40 mg/kg/day (pediatric) or 1,200 mg/day (adult OTC), whichever is lower. The mg/kg sanity-check displayed alongside the result is computed independently from the rounded answer and lets you verify the calculator without re-doing the maths.
Reporting errors. If you believe the tool produced an incorrect output, contact clinicaltoolslibrary.com. Suspected adverse drug events should be reported to the FDA MedWatch programme (US) or the EMA pharmacovigilance system (EU).
The ibuprofen dosage by weight calculator on this page helps parents, carers, and clinicians find the right dose of Motrin® or Advil® (ibuprofen) for a child or adult, using the standard pediatric formula of 10 mg per kilogram of body weight every 6 to 8 hours. This page is an educational reference based on US prescribing information and current American Academy of Pediatrics (AAP) guidance — it does not replace advice from your prescriber or pharmacist.
Enter the weight in pounds or kilograms in the calculator, then cross-check the result against the pediatric chart, infant dosing notes, and safety information further down the page.
How the ibuprofen dosage by weight calculator works
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Converting pounds to kilograms
If you only know the child’s weight in pounds, divide by 2.2 (or multiply by 0.4536) to get kilograms. For example, a 33 lb child weighs roughly 15 kg, so the single dose works out to about 150 mg of ibuprofen. The calculator does the conversion automatically when you switch units.
Children’s Motrin dosage chart (by weight)
The chart below is adapted from the American Academy of Pediatrics’ ibuprofen dosing table and the FDA-approved Motrin / Children’s ibuprofen label available through DailyMed. Dose by weight, not age — children of the same age can vary in size by 30% or more.
| Weight | Dose (mg) | Infant drops 50 mg / 1.25 mL |
Children’s liquid 100 mg / 5 mL |
Chewable 100 mg tab |
|---|---|---|---|---|
| 12–17 lb (5.4–7.7 kg) | 50 mg | 1.25 mL | 2.5 mL | — |
| 18–23 lb (8–10 kg) | 75 mg | 1.875 mL | 4 mL | — |
| 24–35 lb (10.5–15.5 kg) | 100 mg | 2.5 mL | 5 mL | 1 tablet |
| 36–47 lb (16–21 kg) | 150 mg | — | 7.5 mL | 1½ tablets |
| 48–59 lb (21.5–26.5 kg) | 200 mg | — | 10 mL | 2 tablets |
| 60–71 lb (27–32 kg) | 250 mg | — | 12.5 mL | 2½ tablets |
| 72–95 lb (32.5–43 kg) | 300 mg | — | 15 mL | 3 tablets |
| 96+ lb (43.5+ kg) | 400 mg | — | 20 mL | 4 tablets |
Always use the dosing syringe or cup supplied with the product — household teaspoons are not accurate and have been linked to pediatric medication errors. Re-check the strength printed on the bottle before each dose, because brand-name and store-brand bottles share the same 100 mg/5 mL strength now used for both infant and children’s liquid ibuprofen in the United States.
Chewable Motrin tablets dosage chart
Children’s chewable Motrin and generic ibuprofen tablets contain 100 mg per tablet. Most pediatricians reserve chewables for children aged 6 years and older who can chew and swallow safely. Use the right-hand column in the chart above, or follow this quick rule: one 100 mg chewable tablet per 22 lb (10 kg) of body weight, up to four tablets per dose.
Infant ibuprofen dosage by weight
For infants aged 6 months and older, the same 10 mg/kg formula applies. MedlinePlus (NIH) recommends checking with your provider before giving ibuprofen to any child under 2 years old or under 12 lb (5.5 kg). Infants typically need the 50 mg/1.25 mL concentrated drops because the volume is small enough to measure accurately with the supplied oral syringe.
Do not give ibuprofen to babies under 6 months old unless specifically directed by your child’s doctor. The FDA has not approved ibuprofen for this age group, and the safety profile in young infants — particularly for kidney function and gastrointestinal tolerance — is not well established. Refer to the current FDA-approved Motrin Suspension label for the full prescribing information.
When infants should use ibuprofen instead of acetaminophen
Ibuprofen and acetaminophen (Tylenol) are both appropriate first-line antipyretics in children over 6 months. Ibuprofen lasts longer per dose (6 to 8 hours, versus 4 to 6 hours for acetaminophen) and tends to bring fevers down more rapidly, but should be avoided in dehydrated infants, infants vomiting persistently, and those with known kidney problems. If acetaminophen is the better choice, use our pediatric acetaminophen (Tylenol) dosage calculator instead.
Safety, frequency, and when to call a doctor
How often can you give ibuprofen?
Repeat doses no more frequently than every 6 hours, with 8 hours preferred when fever or pain is well controlled. Do not exceed 4 doses in any 24-hour period for children, and avoid giving ibuprofen for more than 3 consecutive days for fever, or more than 10 days for pain, without a clinician’s input.
Maximum daily dose
For children, the maximum is 40 mg/kg per 24 hours. For adults using over-the-counter Motrin or Advil, the ceiling is 1,200 mg per 24 hours (typically 200–400 mg every 4 to 6 hours). Prescription ibuprofen for adults can reach 3,200 mg per day under medical supervision, but this is reserved for inflammatory conditions and short-term use because of cardiovascular, kidney, and gastrointestinal risks. See Drugs.com’s ibuprofen dosing reference for the full set of indication-specific maximums.
When to call your doctor
- Fever lasting more than 3 days in a child, or any fever ≥ 100.4°F (38.0°C) in an infant under 3 months
- Child appears dehydrated (very dry mouth, no wet diaper for 8+ hours, sunken eyes)
- Vomiting after every dose, severe abdominal pain, blood in stool or vomit
- Known kidney disease, NSAID-triggered asthma, bleeding disorders, or a known allergy to ibuprofen, aspirin, or other NSAIDs
- Suspected overdose — call Poison Control (US: 1-800-222-1222) immediately
For a deeper look at how fever is graded by age and core temperature, see our fever temperature converter, and to switch between metric and imperial weights, our pediatric weight converter (lb to kg).
Frequently asked questions about ibuprofen dosage by weight
How much ibuprofen by weight for a child?
The standard single dose is 10 mg per kilogram of body weight (about 4.5 mg per pound), repeated every 6 to 8 hours as needed. A 22 lb (10 kg) child receives roughly 100 mg per dose; a 44 lb (20 kg) child receives roughly 200 mg.
Can babies under 6 months take Motrin?
No, not without specific instructions from a pediatrician. Ibuprofen is not FDA-approved for infants under 6 months, and the AAP recommends avoiding it in this age group unless directed by a doctor.
How often can I give my child Motrin?
Every 6 to 8 hours, with no more than 4 doses in any 24-hour period. Space doses at least 6 hours apart and use the lowest effective dose for the shortest possible time.
What is the maximum daily dose of ibuprofen for a child?
40 mg per kilogram of body weight per 24 hours, capped at the adult OTC ceiling of 1,200 mg in older children. For a 20 kg (44 lb) child, that is 800 mg total per day.
Can I alternate ibuprofen and acetaminophen?
Yes — many pediatricians endorse alternating ibuprofen every 6 hours with acetaminophen every 4 hours when a high fever is hard to control. Keep a written log of each dose, including the time and amount, to avoid double-dosing or exceeding either drug’s daily maximum.
How do I calculate Motrin dose by weight if I only know pounds?
Multiply the child’s weight in pounds by 4.5 to estimate the single dose in mg, or divide pounds by 2.2 to get kilograms first and then multiply by 10. The calculator at the top of this page does the conversion automatically.
Last reviewed: June 2026Published by: Clinical Tools Library. This page is for educational reference only and does not constitute medical advice. Always confirm dose, frequency, and suitability with your prescriber, pharmacist, or pediatrician before giving any medicine.
