Fluids and dosing
IV fluid: maintenance and drip rate
This gives maintenance fluid requirement by the Holliday-Segar (4-2-1) rule, adds any estimated deficit, and converts the hourly rate into drops per minute for a given giving set. It is a starting point that is then titrated clinically.
Enter the values
Leave at 0 if the patient is not dehydrated.
A standard adult set is 15 or 20 drops per mL; a pediatric microdrip set is 60.
The result appears as you type.
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This calculator is provided for reference and education. It does not replace clinical assessment, examination, current guidelines, local protocol, or professional judgment. Verify every result before acting on it. Nirogix accepts no liability for clinical decisions made using this tool.
The formula
- Holliday-Segar: 4 mL/kg/hour for the first 10 kg, 2 mL/kg/hour for the next 10, 1 mL/kg/hour thereafter
- Deficit (mL) = % dehydration × weight (kg) × 10
- Drops per minute = (mL per hour × drop factor) ÷ 60
Worked example
A 25 kg child → (10 × 4) + (10 × 2) + (5 × 1) = 65 mL/hour, which is 1560 mL over 24 hours
When to use it
- Prescribing maintenance fluid
- Setting a drip rate without an infusion pump
And when not to
- Maintenance rates are for a euvolemic patient. Resuscitation is a separate calculation with separate boluses.
- They over-deliver in heart failure, renal failure, and in the critically ill with SIADH.
- Reassess clinically and with electrolytes rather than running the calculated rate unchanged.
References
- The maintenance need for water in parenteral fluid therapy — Holliday MA & Segar WE, Pediatrics, 1957
Last reviewed 07/09/2026.
These calculators are free and always will be. We also build Nirogix, a hospital management system for Indian clinics and hospitals. The same calculations are planned inside the consultation record, pre-filled from the chart.