Fever Triage & Oral Rehydration Fluid Calculator
Check exact age-specific fever action thresholds, calculate hourly oral rehydration goals using the Holliday-Segar / WHO illness fluid method, and review official AAP weight-based pediatric dosing tables.
AAP Weight-Based Pediatric Acetaminophen & Ibuprofen Reference
Pediatric clinicians dose fever-reducers strictly by body weight—never by age alone—and always ask caregivers to measure liquid medications with an oral dosing syringe marked in milliliters (mL), never a household kitchen teaspoon. Remember: treating a fever is optional if a child is sleeping peacefully or playing comfortably; the goal of antipyretics is patient comfort and easier fluid intake, not forcing the thermometer to read 98.6°F.
- Under 12 Weeks Old: Do NOT give any fever reducer before medical evaluation unless specifically instructed by a pediatrician—masking a newborn fever delays emergency workup.
- Under 6 Months Old: NEVER give Ibuprofen (Motrin/Advil) under 6 months of age.
- Under 18 Years Old: NEVER give Aspirin or bismuth subsalicylate (Pepto-Bismol) due to Reye's syndrome risk.
- Check Concentration Labels: US Children's & Infants' liquid Acetaminophen is standardized at
160 mg / 5 mL. Infants' Concentrated Ibuprofen Drops (50 mg / 1.25 mL) are TWICE as concentrated as Children's Liquid Ibuprofen (100 mg / 5 mL)—never mix up the two!
| Child's Weight | Acetaminophen Liquid (160 mg per 5 mL — every 4–6 hrs, max 5 doses/24h) |
Children's Ibuprofen Liquid (Age ≥6 mo ONLY) (100 mg per 5 mL — every 6–8 hrs, max 4 doses/24h) |
|---|---|---|
| 12 – 17 lbs (5.4 – 7.7 kg) | 2.5 mL (80 mg) — Ask MD if <12 wks |
2.5 mL (50 mg) — ONLY if ≥6 months old |
| 18 – 23 lbs (8.2 – 10.5 kg) | 3.75 mL (120 mg) |
3.75 mL (75 mg) — ONLY if ≥6 months old |
| 24 – 35 lbs (10.9 – 15.9 kg) | 5 mL (160 mg) |
5 mL (100 mg) |
| 36 – 47 lbs (16.3 – 21.4 kg) | 7.5 mL (240 mg) |
7.5 mL (150 mg) |
| 48 – 59 lbs (21.8 – 26.8 kg) | 10 mL (320 mg) |
10 mL (200 mg) |
| 60 – 71 lbs (27.2 – 32.2 kg) | 12.5 mL (400 mg) |
12.5 mL (250 mg) |
| 72 – 95 lbs (32.7 – 43.1 kg) | 15 mL (480 mg) |
15 mL (300 mg) |
The "5 mL Every 5 Minutes" Oral Rehydration Technique
When a child or adult with fever or viral gastroenteritis chugs an entire glass of water at once, sudden gastric distension triggers the stretch reflex and causes immediate vomiting. Urgent care clinicians teach the syringe/spoon micro-pacing method: offer 5 mL (1 teaspoon) of balanced Oral Rehydration Solution (Pedialyte, WHO ORS packets) every 5 minutes for the first hour. That small pace quietly delivers 60 mL (2 oz) per hour directly into the small intestine without triggering nausea.
Frequently Asked Questions
Why is a 100.4°F fever in a baby under 3 months old a medical emergency?
Because newborns lack mature immune defenses and behavioral cues, serious bacterial infections (UTI, bacteremia, meningitis) can present with fever as the sole early sign. AAP guidelines call for immediate hospital ED evaluation for any infant under 90 days with a rectal temperature of 100.4°F (38.0°C) or higher.
At what age can a baby safely take Ibuprofen (Motrin / Advil)?
Wait until at least 6 months of age, and avoid ibuprofen even in older children if they are actively vomiting repeatedly or dehydrated, since NSAIDs reduce protective renal blood flow.
Why should children and teenagers never take Aspirin during a fever?
Aspirin and salicylates during viral infections (especially influenza and varicella) carry a documented risk of Reye's syndrome, causing acute hepatic failure and cerebral edema.
📚 Primary Clinical Sources & Guidelines
- American Academy of Pediatrics (AAP) HealthyChildren.org. Acetaminophen and Ibuprofen Dosing Tables for Fever and Pain in Children.
- Pantell RH, et al. Evaluation and Management of Well-Appearing Febrile Infants 8 to 60 Days Old. Pediatrics (AAP Clinical Practice Guideline).
- World Health Organization (WHO) & CDC. Oral Rehydration Therapy (ORT) and Management of Acute Gastroenteritis.