Is 4-2-1 the same as Holiday–Segar?

Yes — 4-2-1 is the hourly form of the classic Holiday–Segar daily method.

Maintenance Fluids (4-2-1)

Pediatrics General Medicine Surgery & Trauma Critical Care

Medical context

Estimate hourly and daily maintenance IV fluid rates with the Holiday–Segar / 4-2-1 rule.

Pediatric teams must confirm age-appropriate references and weight-based dosing with local protocols.

This page explains the Maintenance Fluids formula, how to interpret the output, known limitations, and peer-reviewed references so you can verify results against primary sources and local protocols.

It is grouped under Pediatrics because neonatal and pediatric medical calculators.

How to use this calculator

Enter the values requested by the Maintenance Fluids calculator using the units shown beside each field.
Review the calculated result and read the interpretation section before acting on the output.
Check limitations and references if the result will change management, dosing, or disposition.
Use the related calculators section when you need supporting values (for example electrolytes, weight, or complementary risk scores).

Calculator

Weight (kg)

Result

60 mL/h

1440 mL/day

4 mL/kg/h for first 10 kg, 2 for next 10 kg, 1 thereafter. Maintenance estimate only.

Educational use only. Confirm results with clinical judgment, primary sources, and local protocols. Not a substitute for professional medical advice. Full disclaimer.

Formula

4 mL/kg/h for first 10 kg, 2 mL/kg/h for next 10 kg, 1 mL/kg/h thereafter.

Interpretation

Starting maintenance estimate only — adjust for deficits, losses, cardiac/renal disease, and electrolytes.

Limitations

Not for resuscitation. Neonatal and ICU patients need tailored regimens.

Frequently asked questions

Is 4-2-1 the same as Holiday–Segar?: Yes — 4-2-1 is the hourly form of the classic Holiday–Segar daily method.
Is the Maintenance Fluids result enough to make a treatment decision?: No. Calculators support medical decision-making but do not replace examination, shared decision-making, institutional protocols, or consultant input when stakes are high.
Does Calcmedical store the values I type in?: Inputs are processed in your browser for this session. We do not ask for patient names or medical record numbers. See our privacy policy for hosting and analytics details.

References

Holiday MA, Segar WE. Pediatrics. Maintenance fluids.