Calculator

Electrolyte Correction

Sodium deficit / free water deficit and potassium replacement estimates. Always correct slowly and re-check labs.

Na deficit (mEq) = TBW × (desired Na − measured Na) · FWD (L) = TBW × (Na/140 − 1)

DevIn development. Formulas (TBW, Na deficit, FWD, empirical K deficit) are not yet clinically reviewed. Use as an estimate only and verify with your local protocol before prescribing.

Patient weight

TBW estimate

Section

Sodium correction

Measured Na

mmol/L

Desired Na

mmol/L

Do not correct chronic hyponatremia faster than 8 mmol/L per 24 h to avoid osmotic demyelination syndrome.

Sodium deficit

—mEq

Total body water

—L

Min. correction time (at 8 mEq/L/24h)

—h

Enter weight and sodium values.

Section

Potassium replacement

Measured K⁺

mmol/L

Peripheral IV: max 10 mEq/h & ≤ 40 mEq/L. Central line: up to 20 mEq/h with cardiac monitoring. Correct underlying Mg deficiency in parallel.

Estimated K deficit

—mEq

Infusion time (peripheral · 10 mEq/h)

—h

Infusion time (central · 20 mEq/h)

—h

Enter weight and potassium values.