Fluid Requirement Calculator (Holliday–Segar)
Fluid Requirement Calculator (Holliday–Segar)
The Holliday–Segar method, developed in 1957 by Drs. Malcolm Holliday and William Segar, remains the most widely used formula for calculating maintenance fluid requirements in children. Published in the journal Pediatrics, this simple weight-based method estimates the daily water needs of children requiring IV fluids, and is taught in virtually every pediatric and nursing training program worldwide.
The Holliday–Segar formula divides a child’s weight into tiers, with each tier receiving a different fluid allocation per kilogram. The method is endorsed by the American Academy of Pediatrics (AAP) and is the standard taught in Pediatric Advanced Life Support (PALS) courses. It is used both for calculating total daily fluid needs and for determining hourly IV fluid rates.
The Holliday–Segar Formula
- First 10 kg: 100 mL/kg/day = 4 mL/kg/hr
- Second 10 kg (11–20 kg): 50 mL/kg/day = 2 mL/kg/hr
- Each kg above 20 kg: 20 mL/kg/day = 1 mL/kg/hr
For example, a 25 kg child would need: (10 × 100) + (10 × 50) + (5 × 20) = 1,000 + 500 + 100 = 1,600 mL/day, or approximately 67 mL/hour.
Important Considerations
The AAP’s 2018 clinical practice guideline updated recommendations for maintenance IV fluids in children, emphasizing the use of isotonic fluids (rather than hypotonic fluids) to prevent hyponatremia in most hospitalized children. The Holliday–Segar method calculates the volume of fluid needed; the type of fluid should be determined by the treating physician based on the child’s clinical condition, electrolyte status, and the AAP guidelines.
Fluid Requirement Calculator
Holliday–Segar Fluid Requirement Calculator
Frequently Asked Questions
What is the Holliday-Segar method?
It estimates daily maintenance fluid needs by weight: 100 mL/kg/day for the first 10 kg, 50 mL/kg/day for the next 10 kg, and 20 mL/kg/day for each kg above 20. It was published in 1957 and remains the standard for pediatric maintenance fluids.
How do I calculate fluids for a 25 kg child?
First 10 kg: 1,000 mL. Next 10 kg: 500 mL. Last 5 kg: 100 mL. Total = 1,600 mL/day, about 67 mL/hour. The calculator does this automatically.
Is isotonic or hypotonic fluid recommended?
The AAP 2018 guideline recommends isotonic maintenance fluids (such as 0.9% NaCl with added dextrose and potassium) for most hospitalized children to reduce the risk of hospital-acquired hyponatremia.
Can I use this for oral hydration at home?
This calculator estimates total daily fluid needs and is primarily a clinical reference. For mild dehydration at home, follow your pediatrician’s advice on oral rehydration solution volumes – typically small, frequent amounts.
Authoritative Resources
Written by Dr. Sarah Williams, MD (Pediatrics) | Medically approved by Dr. Ahmed Raza, MD (Pediatrics) | Updated for 2026
Disclaimer: This calculator is for general informational purposes only and is not a substitute for professional medical advice. Always consult your pediatrician.
