Urine Output Calculator

Written by Great Medico

Updated September 24, 2026 •2 min read

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Some urologic measurements look simple but can be misleading without their formula. Urine Output Calculator turns the fields shown in this tool into the specific result it was built to calculate.

What this calculator does

Urine Output Calculator uses Patient age, Weight, Time, Urine volume, and Fluid intake to calculate weight-normalized urine output. Where supported, it also shows Reference threshold and Net intake minus urine 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. Kidney and urologic calculations often summarize one narrow measurement or historical model. Results should be read with symptoms, laboratory trends, imaging, pathology, and the clinical question that prompted the test.

How to use it

Enter or select Patient age, Weight, Time, Urine volume, and Fluid intake. 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

Urine output rate equals urine volume divided by body weight and elapsed time, producing mL/kg/hour. The tool compares that rate with its built-in age reference of 2 mL/kg/h for infants, 1 for children, or 0.5 for adults, and also shows fluid intake minus urine volume.

Example

Using the sample values prefilled in this calculator, the primary result is 1.429 mL/kg/h (Urine output at/above common age-group reference), Reference threshold is 0.5 mL/kg/h, and Net intake minus urine is 400 mL. 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 urine output at/above common age-group reference from this specific urology/kidney model. It is best used to organize the entered measurements, not as a stand-alone diagnosis or individual prognosis.

Limitations and notes

Oliguria definitions depend on age, duration, fluid status, kidney function, and clinical setting. Intake minus urine is not complete fluid balance because it omits other inputs and losses.