Free Water Deficit Calculator – Accurate Fluid Replacement Estimator for Hypernatremia
Free Water Deficit Calculator
Are you managing a case of dehydration or hypernatremia? Our Free Water Deficit Calculator helps healthcare professionals and students accurately determine the amount of fluid replacement needed to restore a patient’s serum sodium level to a safe and optimal range. This tool is based on clinically approved formulas and is essential in scenarios involving water loss and electrolyte imbalance.
What is Free Water Deficit?
Free water deficit (FWD) is the volume of water a person is lacking to return their sodium concentration to normal (usually around 140 mEq/L). This occurs when sodium levels rise due to excessive water loss, commonly seen in conditions like fever, diarrhea, or diabetes insipidus.
Why Use This Calculator?
- Accurate results based on patient’s age, sex, and weight
- Built-in formula: TBW × ((Current Na⁺ / Desired Na⁺) – 1)
- Customizable for children, adults, and elderly patients
- Suitable for use in hospital, academic, and research settings
How to Use:
- Select the patient’s age/sex category
- Enter body weight in kilograms
- Input the current serum sodium level
- Set the desired sodium value (default is 140 mEq/L)
- Click “Calculate” to get the result in liters
This value helps clinicians decide how much free water (usually via IV fluids or oral rehydration) is required to safely normalize sodium levels.
Disclaimer: This calculator is for educational and informational purposes only. Always consult a licensed healthcare provider for clinical decisions.
