Estimate a free-water deficit from total-body-water assumptions and a sodium target.
Free Water Deficit Hypernatremia
Form
Results
Free Water Deficit
0L
Table of Contents
1
What is Free Water Deficit Hypernatremia?
2
How to Use This Calculator
- Enter or select Gender, Age range, Weight, Sodium, Sodium desired.
- Check the unit beside each measurement. For a percentage or rate, use the scale and time period stated in the form.
- Choose Calculate, then compare the output with the formula and example below. If you change a value or option, calculate again to update the result.
3
Formula Used
Deficit = estimated total body water × (current sodium/desired sodium−1).
4
Variables Explained
| Input | What it means |
|---|---|
| Gender | Select the equation or reference category that applies to the measurement being assessed. |
| Age range | Age in the time unit shown; most adult equations use completed years. |
| Weight | Measured mass in the chosen unit; pounds and kilograms are not numerically interchangeable. |
| Sodium | Sodium concentration, normally in mmol/L or mEq/L; follow the form’s unit label. |
| Sodium desired | Sodium concentration, normally in mmol/L or mEq/L; follow the form’s unit label. |
5
Worked Example
Total body water 42 L, sodium 154 and target 140 give an estimated deficit of 4.2 L.
6
Why Use This Calculator?
Use the calculation to make the method and its inputs easier to check with a healthcare professional. Its meaning depends on the clinical setting and on whether the underlying method is appropriate for that person.
7
Common Mistakes
- This is not a replacement-fluid prescription; timing, ongoing losses and clinical monitoring are essential.
8
Frequently Asked Questions
Is this result a diagnosis or treatment instruction?
No. It describes a calculation or score from the supplied information. A qualified clinician must check the measurements, the method’s applicability and the wider clinical picture.
Can I enter the units from any lab report?
Use the units specified in the form and select a conversion only where the page provides one. Different substances need different conversion factors; a mismatch can produce a plausible but incorrect result.
9
