Free Water Deficit Calculator
Estimate free water deficit for hypernatremia using the standard clinical formula, with inputs for weight and current/target sodium.
Result
Water Deficit:
0.00 L
The Formula (Clinical Gold Standard)
Water Deficit = Weight (kg) × ((Current Na / Target Na) − 1)
FAQ
What is hypernatremia?
Too much sodium in the blood, usually due to water loss/dehydration.
Why is water deficit correction important?
It prevents the risks of rapid shifts (brain injury, edema, seizures). Careful staged correction is lifesaving.
Does this apply to children?
Yes—use actual body weight and consult a pediatrician for the rate of sodium change. Pediatric guidelines may vary.
Can I use this for hyponatremia?
No, the formula and risks are different for sodium deficiency.
Tool by Ugo Candido. Data: MDCalc, Last review: 2025.
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted text)
Water Deficit = Weight (kg) × ((Current Na / Target Na) − 1)
Variables and units
- No variables provided in audit spec.
Sources (authoritative):
- Home — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/ - Health & Fitness — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/health-fitness - MDCalc — mdcalc.com · Accessed 2026-01-19
https://www.mdcalc.com/calc/113/free-water-deficit-hypernatremia - Dog Calorie (Vet) — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/dog-calorie - BMI Calculator — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/bmi-calculator - GFR (Kidney Function) — calcdomain.com · Accessed 2026-01-19
https://calcdomain.com/gfr
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
- Initial audit spec draft generated from HTML extraction (review required).
- Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
- Confirm sources are authoritative and relevant to the calculator methodology.