Daily Fluid Requirements Calculator
Estimates a patient's daily fluid needs using the Holliday-Segar method, a tiered weight-based formula. Used by clinicians and nurses to calculate maintenance IV fluids or oral fluid targets for pediatric and adult patients.
About this calculator
The Holliday-Segar method calculates daily maintenance fluid requirements in mL/day based on body weight in kilograms using a three-tier formula. For the first 10 kg of body weight, the requirement is 100 mL/kg/day. For weight between 10 and 20 kg, an additional 50 mL/kg/day is added above the base of 1,000 mL. For every kilogram above 20 kg, only 20 mL/kg/day is added to the base of 1,500 mL. Expressed as a formula: Fluid (mL/day) = 100×weight if ≤10 kg; 1000 + 50×(weight−10) if 10–20 kg; 1500 + 20×(weight−20) if >20 kg. This method reflects the metabolic rate of different body-size tiers and is the standard approach for pediatric fluid management in clinical settings.
How to use
Suppose a child weighs 25 kg. Since 25 kg exceeds 20 kg, we use the third tier: Fluid = 1500 + 20 × (25 − 20) = 1500 + 20 × 5 = 1500 + 100 = 1,600 mL/day. Now try a 15 kg child: weight is between 10–20 kg, so Fluid = 1000 + 50 × (15 − 10) = 1000 + 250 = 1,250 mL/day. Simply enter the patient's weight in kg and the calculator applies the correct tier automatically, returning the daily fluid target in milliliters.
Frequently asked questions
What is the Holliday-Segar method and why is it used for fluid calculations?
The Holliday-Segar method, published in 1957, estimates daily maintenance fluid needs based on caloric expenditure, which closely correlates with body weight. It uses three weight tiers—up to 10 kg, 10–20 kg, and above 20 kg—each with a decreasing rate per kilogram to reflect diminishing metabolic demand. It is widely used in pediatric medicine to guide IV fluid orders and oral intake goals. Its simplicity and clinical validation have made it the standard maintenance fluid formula in hospitals worldwide.
How do you calculate daily fluid requirements for a 30 kg child?
For a 30 kg child, the third tier of the Holliday-Segar formula applies: 1500 + 20 × (30 − 20) = 1500 + 200 = 1,700 mL/day. This can also be expressed as approximately 70 mL/hour when converted for IV drip rate planning. Always confirm with clinical guidelines and adjust for fever, losses, or renal conditions. The formula provides a starting estimate, not a fixed prescription.
When should daily fluid requirements be adjusted beyond the Holliday-Segar calculation?
The Holliday-Segar formula provides baseline maintenance fluid needs under normal conditions. Adjustments are necessary when patients have fever (increasing insensible losses), diarrhea or vomiting, burns, renal impairment, heart failure, or SIADH. Critically ill patients often require individualized fluid management guided by clinical assessment and lab values. Always use this calculator as a starting point and consult clinical judgment for patients with complicating conditions.