Pediatric Urine Output Calculator

About this calculator

Urine output normalized to body weight and time — expressed in mL/kg/hr — is a core bedside indicator of renal perfusion and hydration status in children, since kidney output responds quickly to changes in blood volume and blood pressure. Adequate output is generally considered to be at least 1 mL/kg/hr in infants and young children, with a somewhat lower threshold around 0.5 mL/kg/hr often used for older children and adolescents; sustained output below the relevant threshold is termed oliguria and prompts closer clinical evaluation.

This calculator takes urine volume, the child's weight, and the collection time period, and returns the output rate in mL/kg/hr. Pediatric ICU and ward nurses, and pediatricians monitoring a hospitalized child's fluid balance use it to standardize output tracking across patients of very different sizes, since a raw milliliter count means little without adjusting for body weight — this is a monitoring calculation, not a diagnostic or treatment tool.