Maintenance Fluids Calculator
Determine daily and hourly IV fluid requirements using the Holliday-Segar method, with optional adjustments for fever or increased insensible loss.
Results
Daily maintenance
1400 mL/day
Hourly rate (4-2-1 rule)
56.0 mL/hr
How to Use This Calculator
Collect an accurate weight
Use the most recent weight measured in kilograms (convert if necessary).
Apply Holliday-Segar
Calculator automatically applies 100/50/20 mL/kg/day or the 4-2-1 hourly rule.
Adjust for clinical factors
Increase for fever, phototherapy, or diarrhea; decrease for renal/cardiac issues per physician orders.
Formula
Daily maintenance:
Source: Holliday MA, Segar WE. The maintenance need for water in parenteral fluid therapy. Pediatrics. 1957.
Frequently Asked Questions
Why use the 4-2-1 rule?
It derives from Holliday-Segar and provides an hourly infusion rate for IV drips.
When should I use ideal body weight?
In obese children or adolescents, use ideal/lean body weight to avoid overhydration.
How do I replace deficit or ongoing losses?
Calculate deficit separately (e.g., dehydration) and add to maintenance; replace losses mL-for-mL as ordered.
Is hypotonic fluid still recommended?
Current guidelines favor isotonic solutions (NS, LR) due to risk of hyponatremia with hypotonic maintenance fluids.
Do neonates follow the same formula?
Premature neonates have higher insensible losses. Follow NICU-specific protocols.