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Potassium Deficit Calculator and Formula

Potassium deficit calculator and formula for a rough total-body estimate and monitored hypokalemia replacement considerations.

Please enter a potassium level between 1.0 and 7.0 mEq/L.

How the Potassium Deficit Estimate Works

This calculator uses the rough clinical relationship that each 0.3 mEq/L decrease below the 4.0 mEq/L target may represent about 100 mEq of total-body potassium deficit. The estimate is not reliable in redistribution states and must not be used as a direct replacement order.

References and Safety Notes

This page provides a rough potassium deficit estimate and safety guidance only. Potassium replacement orders must follow local protocol with renal function, urine output, ECG risk, infusion route, concentration limits, magnesium status, and repeat serum potassium monitoring.

  • StatPearls - Potassium Reference for oral/IV potassium administration, infusion-rate cautions, renal impairment cautions, and ECG/monitoring requirements.
  • StatPearls - Hypokalemia Reference for hypokalemia management, magnesium correction, monitoring frequency, and the rough total-body potassium deficit rule.
  • Local hospital potassium replacement protocol Institutional concentration, route, central/peripheral line, and maximum infusion-rate policies should override generic estimates.

Frequently Asked Questions

How is potassium deficit estimated?

This tool uses the rough clinical relationship that each 0.3 mEq/L decrease below the selected target may represent about 100 mEq of total-body potassium deficit. The estimate is unreliable in redistribution states and is not a replacement dose.

Can the estimated potassium deficit be replaced all at once?

No. Route, concentration, infusion rate, renal function, urine output, ECG findings, magnesium, and repeat potassium measurements determine safe replacement.

Why can serum potassium differ from total-body potassium?

Insulin, acid-base changes, medications, cell breakdown, and renal function can shift potassium between cells and blood, so the serum value may not directly represent total-body stores.

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