Pediatric Maintenance Fluid Calculator
Use the Holliday-Segar method to estimate daily and hourly maintenance fluids for children.
Formula is calculated in kilograms automatically.
What is the Holliday-Segar formula?
The Holliday-Segar formula is a standard pediatric method for estimating maintenance fluid requirements. It gives clinicians a practical starting point for IV or oral fluid planning in children who are not drinking enough on their own.
It is commonly taught in pediatrics, emergency medicine, anesthesia, and critical care because it is simple, fast, and generally reliable for initial estimates.
Holliday-Segar formula at a glance
Daily maintenance (100/50/20 rule)
| Weight Band | Daily Fluid Requirement |
|---|---|
| First 10 kg | 100 mL/kg/day |
| Second 10 kg (10-20 kg) | 50 mL/kg/day |
| Each kg above 20 kg | 20 mL/kg/day |
Hourly maintenance (4/2/1 rule)
- First 10 kg: 4 mL/kg/hour
- Second 10 kg: 2 mL/kg/hour
- Each kg above 20 kg: 1 mL/kg/hour
Worked examples
Example 1: 8 kg infant
Daily: 8 × 100 = 800 mL/day
Hourly: 8 × 4 = 32 mL/hour
Example 2: 17 kg child
Daily: (10 × 100) + (7 × 50) = 1000 + 350 = 1350 mL/day
Hourly: (10 × 4) + (7 × 2) = 40 + 14 = 54 mL/hour
Example 3: 32 kg child
Daily: 1500 + (12 × 20) = 1500 + 240 = 1740 mL/day
Hourly: 60 + (12 × 1) = 72 mL/hour
When to use caution
The calculator provides an estimate, not a complete clinical order. Real-world fluid decisions may differ based on diagnosis and current physiology.
- Shock, sepsis, burns, major trauma, or significant dehydration
- Renal disease, heart failure, liver disease, SIADH, or endocrine disorders
- Neonates and medically complex infants who need specialist protocols
- Patients with electrolyte abnormalities or altered urine output
Practical bedside tips
- Reassess hydration status frequently (vitals, exam, urine output, labs).
- Choose fluid type based on institutional protocol and patient condition.
- Adjust for fever, losses (vomiting/diarrhea), drains, and NPO duration.
- In hospitalized patients, monitor sodium trends to avoid dysnatremia.
Bottom line
The Holliday-Segar method is a strong starting point for pediatric maintenance fluids. Use it for quick, structured estimates, then individualize with clinical judgment and ongoing reassessment.
Educational use only. This page does not replace professional medical advice, diagnosis, or treatment.