Hyponatraemia / Hypernatraemia Correction Calculator

1. Sodium disorder

Age

Years for adults; enter age in years for this calculator.

Sex

Weight

Current serum sodium

mmol/L

Target sodium

mmol/L

Desired correction rate

mmol/L/hour

2. Clinical assessment

Neurological severity

Likely duration

Clinical volume status

Volume status cannot be reliably determined from sodium alone.

Fluid being considered

Important: Volume status is a clinical diagnosis based on examination, blood pressure/perfusion, urine output, history, fluid losses, oedema and other findings. This calculator does not diagnose hypovolaemia, euvolaemia or hypervolaemia from sodium alone.

3. Current assessment

— Severity

— Estimated total body water

— Target sodium change

— Approx. time at selected rate

4. Sodium / water requirement

5. Predicted sodium change from selected IV fluid

Fluid volume

Fluid sodium

mmol/L

Predicted sodium change

mmol/L

6. Estimated fluid volume to reach the selected target

Maximum sodium change to use for calculation

mmol/L

Estimated volume of selected fluid

Do not interpret this as an automatic infusion order. The Adrogué–Madias prediction is an estimate. Actual sodium response can differ substantially because of urine output, ongoing losses, renal function and changes in free-water handling.

7. Correction-rate safety check

What should I do now?

8. Reassessment calculator

Previous sodium

mmol/L

New sodium

mmol/L

Time interval

hours

Enter the repeat sodium and calculate the actual rate of correction.

9. Severity reference

Disorder	Mild	Moderate	Severe
Hyponatraemia	130–134	125–129	<125 mmol/L
Hypernatraemia	146–149	150–169	≥170 mmol/L

These categories are intended as an educational framework. Local protocols may use different definitions, particularly in neonates and young children.

Sodium Correction Calculator

1. Sodium disorder

2. Clinical assessment

3. Current assessment

4. Sodium / water requirement

5. Predicted sodium change from selected IV fluid

6. Estimated fluid volume to reach the selected target

7. Correction-rate safety check

What should I do now?

8. Reassessment calculator

9. Severity reference