Urine Osmolality Calculator

The Urine Osmolality Calculator estimates urine concentration based on laboratory values for sodium, potassium, urea, and glucose. This tool helps healthcare professionals and patients assess kidney function and hydration status. Whether you are evaluating dehydration, diagnosing diabetes insipidus, or monitoring fluid balance, this calculator provides immediate, reliable clinical insights.

Range: 50-200 mEq/L (mmol/L)
Range: 10-100 mEq/L (mmol/L)
Range: 5-60 mg/dL
Range: 0-500 mg/dL (optional)

How Urine Osmolality Is Calculated

Urine osmolality measures the concentration of dissolved particles in your urine, which reveals how effectively your kidneys manage water balance. The calculation relies on a specific formula that accounts for the distinct behavior of electrolytes and organic solutes.

2 × Sodium + 2 × Potassium + (Urea × 0.166) + (Glucose × 0.0555)

Where:

  • Sodium and Potassium are in mEq/L
  • Urea and Glucose are in mg/dL

First, the calculator takes sodium and potassium values and multiplies them by two. This adjustment is necessary because these electrolytes separate into two distinct particles in solution. Next, it converts urea and glucose measurements using specific factors to match the osmolality units. This precise method is clinically trusted for evaluating kidney concentrating ability and hydration status accurately.

By combining these converted values, the tool delivers a total osmolality score that reflects the total particle count in the urine.

What Your Urine Osmolality Means

This number indicates whether your urine is dilute or concentrated, providing a clear picture of your hydration status and kidney health.

Normal Range (300-900 mOsm/kg)

This result suggests your kidneys are effectively balancing water levels and you are well-hydrated. You should continue your current fluid intake habits to maintain this healthy state.

Low Result (<300 mOsm/kg)

This implies very dilute urine, which can result from drinking too much water or kidney issues like diabetes insipidus. If this persists despite normal fluid intake, you should consult a doctor to check your kidney's concentrating ability.

High Result (>900 mOsm/kg)

This signals concentrated urine and usually indicates dehydration. You need to drink more water immediately to help your kidneys function properly and restore your body's fluid balance.

Important: This calculator is for educational purposes only and does not replace a professional medical diagnosis. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

Monitoring your results over time helps you identify trends and discuss them effectively with your doctor for better health management.