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Urine Output Calculator

Urine output calculator determines weight-based urine production in mL/kg/hr to assess kidney perfusion. Normal adult output is above 0.5 mL/kg/hr, with oliguria below 0.5 and anuria below 0.1 mL/kg/hr.

Enter Values

Urine Volume (mL)

Patient Weight (kg)

Collection Time (hrs)

Result

Enter values above and click Calculate to see your result.

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Our AI assistant provides general estimates and advice only. Please consult a qualified healthcare professional before making any health-related decisions.

Formula

Core Formula

\text{Urine Output} = \frac{\text{Volume (mL)}}{\text{Weight (kg)} \times \text{Hours}}

How it works: Standardizes urine volume by patient weight and observation time to identify oliguria.

Worked Example

500 mL over 8 hours in a 70kg patient -> 0.89 mL/kg/hr.

Urine Output Calculator - mL/kg/hr for Kidney Function

Weight-based urine output is a critical marker of kidney perfusion and function, especially in hospitalized and critically ill patients. It helps detect acute kidney injury early.

Formula: Urine Output (mL/kg/hr) = Total Volume (mL) / Weight (kg) / Time (hours)
Normal adult: above 0.5 mL/kg/hr; pediatric: above 1.0 mL/kg/hr for infants
Oliguria: below 0.5 mL/kg/hr for more than 6 hours (KDIGO Stage 1 AKI criterion)
Anuria: below 0.1 mL/kg/hr or less than 50 mL total output per day
A key monitoring parameter during fluid resuscitation, sepsis management, and post-operative care

This calculator is for educational purposes only. Urine output trends should be interpreted alongside clinical status, hemodynamics, and other renal markers by a healthcare professional.

You can also calculate changes using our IV Drip Rate Calculator or FeNa Calculator.

Frequently Asked Questions

What is a normal urine output?

In adults, normal output is above 0.5 mL/kg/hr. For infants, it is typically above 1.0 mL/kg/hr, and for older children above 0.5 mL/kg/hr.

What is oliguria?

Oliguria is defined as urine output below 0.5 mL/kg/hr in adults sustained for more than 6 hours. It is a KDIGO Stage 1 criterion for acute kidney injury.

What is anuria?

Anuria is defined as urine output below 0.1 mL/kg/hr or less than 50 mL total per day. It suggests severe kidney impairment or complete obstruction.

Why use mL/kg/hr instead of total volume?

Weight-based calculation provides a standardized metric across different body sizes, ensuring fair evaluation whether the patient weighs 50 kg or 100 kg.

How does urine output relate to AKI staging?

Under the KDIGO criteria, Stage 1 AKI includes oliguria (below 0.5 mL/kg/hr) for 6-12 hours. Stage 2 is below 0.5 for 12+ hours. Stage 3 is anuria (below 0.3 mL/kg/hr) for 24+ hours.

Is this calculator a substitute for medical advice?

No. This tool is for educational purposes only. Always consult a healthcare professional for clinical decisions related to fluid management and kidney function.

How can I put this Urine Output Calculator on my blog or website?

Yes, the Urine Output Calculator is fully embeddable. Tap "Embed" above to configure appearance and copy the code. It is free to use, works on any platform (HTML, WordPress, CMS), and adjusts to any screen size automatically. Visit calculory.com/services/embed-calculators for the complete guide.

Medical Disclaimer

This calculator is provided for informational and educational purposes only. It is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider before making any decisions based on these results. Do not disregard or delay seeking medical advice because of information obtained from this tool.

AI Assistant

Ask about this calculator

I can help you understand the urine output calculator formula, interpret your results, and answer follow-up questions.

Try asking

Our AI assistant provides general estimates and advice only. Please consult a qualified healthcare professional before making any health-related decisions.

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IV Drip Rate Calculator FeNa Calculator

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