Maintenance Fluids Calculator

Written by Great Medico

Updated September 24, 2026 •2 min read

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Small differences in pediatric inputs can change the answer quickly. Maintenance Fluids Calculator keeps the calculation focused on the age, weight, measurements, or clinical branch actually implemented in the plugin.

What this calculator does

Maintenance Fluids Calculator uses Weight to calculate pediatric maintenance-fluid requirement. Where supported, it also shows 4-2-1 hourly rate so the primary result is easier to check. It follows the exact field flow and engine behavior in this plugin rather than describing a different calculator with the same name. Children are not simply small adults: age, weight, gestational history, formulation, and clinical setting can change how a result should be used. Pediatric outputs deserve extra attention to units and the population for which the method was developed.

How to use it

Enter or select Weight. Use the units offered by the calculator and keep paired laboratory or treatment values from the same clinical episode whenever the formula assumes that. If an entry is unknown, do not substitute a guess simply to obtain a number.

How the calculation works

Daily maintenance fluid uses the 100/50/20 rule: 100 mL/kg for the first 10 kg, 50 mL/kg for the next 10 kg, and 20 mL/kg for each kilogram above 20. The hourly rate uses the parallel 4-2-1 rule.

Example

Using the sample values prefilled in this calculator, the primary result is 1500 mL/day (Maintenance fluid requirement) and 4-2-1 hourly rate is 60 mL/h. This example demonstrates the plugin’s own calculation path; replace the sample inputs with verified values before interpreting a real result.

How to interpret the result

Read the output as maintenance fluid requirement from this pediatric method. Age, weight, measurement quality, gestational history, and the child’s clinical state determine whether the number is useful or needs a different validated pathway.

Limitations and notes

Children are not simply small adults: age, weight, gestational history, formulation, and clinical setting can change how a result should be used. Pediatric outputs deserve extra attention to units and the population for which the method was developed. When a result could change urgent care or medication dosing, confirm the child’s current weight, age, units, and clinical context before acting.