Last updated October 10, 2026 · Report an error
Computes urine output rate in mL/kg/hr from a measured urine volume, time period, and patient weight — pure arithmetic: rate = volume (mL) / (weight (kg) x time (hours)). The commonly cited oliguria threshold is under 0.5 mL/kg/hr, cited here for reference only. For general reference and educational purposes only — not a medical diagnosis. Consult a doctor or nurse for actual fluid status assessment.
How it works
Enter urine volume in mL, the time period in hours, and patient weight in kg. The tool divides volume by weight and time.
- Enter urine volume (mL).
- Enter time period (hours).
- Enter patient weight (kg).
- Click Calculate to see your results.
Examples
Volume 250 mL, time 4 hours, weight 70 kg
Rate = 250 / (70 x 4) = 250 / 280 ≈ 0.89 mL/kg/hr — at or above the commonly cited oliguria threshold.
Who should use it
- Monitoring fluid status in a hospital or critical care setting.
- Nursing education about urine output monitoring.
Industry applications
- Critical care and nursing reference
- Hospital fluid balance monitoring
Advantages
- Simple, standard nursing/critical care arithmetic.
- Quick reference against the commonly cited oliguria threshold.
Limitations
- A snapshot — trends over time are more clinically meaningful than a single measurement.
- Does not account for fluid balance more broadly (intake, insensible losses).
Common mistakes to avoid
- Using total body weight when a protocol calls for ideal or adjusted body weight (check your specific clinical context).
- Averaging output over too short a time window, which can be noisy.
Best practices
- Track urine output rate over a consistent, several-hour window for a more meaningful trend rather than a single short interval.
Tips
- Urine output is typically tracked as a trend over several hours rather than judged from a single hour's measurement.
Frequently asked questions
Yes, with no signup and no limit on how many calculations you run.
A commonly cited threshold is under 0.5 mL/kg/hr sustained over several hours, cited here for reference only — not an interpretation of any specific patient.
Use the actual measured time period over which the urine volume was collected (commonly a several-hour window in a clinical monitoring setting).
No — this is arithmetic on measured values. Consult a doctor or nurse for actual fluid status assessment.