M+QuickMedCalc
Educational reference only. Not a diagnostic tool. See full disclaimer.
RenalUrine Output

Urine Output Calculator (mL/kg/hr)

Calculate total, hourly, and weight-normalized urine output.

Content updated: View sources

mL

Total volume

—

Urine output

—

Weight-normalized urine output

—

About

This calculator expresses a measured urine volume as mL/hour and mL/kg/hour over a specified interval. Adult KDIGO urine-output criteria require defined durations and clinical context; this page does not assign an AKI stage. Pediatric and neonatal reference thresholds differ and are not automatically applied.

Formula

Urine output (mL/hr) = volume / elapsed hours
Urine output (mL/kg/hr) = volume / weight (kg) / elapsed hours
Minutes are converted to hours; pounds are converted to kilograms

Interpretation

Interpretation: Consider the full time window, catheter patency and measurement accuracy, current volume status, ongoing losses, diuretic exposure, kidney function, and circulation.

Limitations: A short or isolated observation should not be treated as an AKI classification. Age-specific thresholds require separate assessment.

Worked example: 350 mL over 10 hours at 70 kg equals 35 mL/hr and 0.50 mL/kg/hr.

References

  1. KDIGO Clinical Practice Guideline for Acute Kidney Injury. Kidney Int Suppl. 2012;2:1-138.
  2. Kellum JA, et al. Kidney Disease: Improving Global Outcomes AKI Work Group guideline summary. Crit Care. 2013.

FAQ

Related Calculators

eGFR

Estimate glomerular filtration rate using the CKD-EPI equation.

UPCR

Calculate spot urine total protein-to-creatinine ratio in mg/mg and mg/g.

IV Fluid Rate

Calculate pediatric maintenance estimates or adult reference ranges.

Disclaimer

Educational and informational reference only. Not intended to replace professional medical advice, diagnosis, treatment, or independent verification.