Urine Output Calculator
Calculate urine output rate and fluid balance for kidney function assessment
Calculate Urine Output
Patient Information
Enter patient's body weight in kilograms
Time period over which urine was collected (typically 24 hours)
Measurements
Total volume of urine collected during observation period
Total oral and IV fluid intake during observation period
Urine Output Results
Normal Urine Output Ranges
Adults (≥18 years)
| Range (ml/kg/hr) | Classification |
|---|---|
| <0.5 | Oliguria |
| 0.5-5.0 | Normal |
| >5.0 | Polyuria |
Children (<18 years)
| Range (ml/kg/hr) | Classification |
|---|---|
| <1.0 | Oliguria |
| 1.0-3.0 | Normal |
| >3.0 | Polyuria |
Example Calculation
Adult Patient Example
Patient: 25-year-old adult, 70 kg
Observation period: 24 hours
Urine collected: 1,800 ml
Fluid intake: 2,200 ml
Calculation
Urine output rate = 1,800 ml / (70 kg × 24 hr)
Urine output rate = 1,800 / 1,680
Urine output rate = 1.07 ml/kg/hr
Fluid balance = 2,200 - 1,800 = +400 ml
Interpretation: Normal urine output for adults (0.5-5.0 ml/kg/hr)
Medical Disclaimer
This calculator is for educational purposes only and should not replace professional medical assessment. Urine output monitoring requires clinical context and should always be evaluated by qualified healthcare professionals. Oliguria may indicate acute kidney injury, dehydration, or other serious conditions requiring immediate medical attention.
Quick Reference
Normal Ranges
Formula
Clinical Significance
Monitor kidney function and fluid status
Detect acute kidney injury early
Assess response to fluid therapy
Guide ICU and surgical care
Important Notes
Include all fluid losses (skin, lungs, stool)
Consider patient's clinical condition
Oliguria <0.5 ml/kg/hr needs urgent evaluation
Monitor trends, not just single values
Understanding Urine Output Monitoring
What is Urine Output?
Urine output is the volume of urine produced by the kidneys over a specific time period, typically measured in milliliters per kilogram of body weight per hour (ml/kg/hr). It's a crucial indicator of kidney function and fluid balance.
Why Monitor Urine Output?
- •Early detection of acute kidney injury
- •Assessment of fluid balance
- •Monitoring response to treatment
- •Guiding fluid replacement therapy
Clinical Conditions
Oliguria (<0.5 ml/kg/hr adults)
- • Acute kidney injury
- • Severe dehydration
- • Shock or hypotension
- • Urinary obstruction
Polyuria (>5 ml/kg/hr adults)
- • Diabetes mellitus
- • Diabetes insipidus
- • Diuretic medications
- • Excessive fluid intake
Fluid Balance Assessment
Fluid balance calculation helps assess whether a patient is maintaining proper hydration. A negative balance may indicate dehydration, while a positive balance could suggest fluid overload. Clinical correlation is essential for proper interpretation.
Factors Affecting Fluid Balance
- • Insensible losses (respiratory, skin) ~800-1000 ml/day
- • Fever increases losses ~200 ml/day per °C above 37°C
- • Gastrointestinal losses (diarrhea, vomiting)
- • Medications (diuretics, ACE inhibitors)