Potassium Supplementation Calculator (KCl in IV Fluids)
How much potassium to add per litre of fluid for the patient's serum potassium, and a check of the resulting mEq/kg/h.
Results are calculated in your browser. Always double-check before administering and use your clinical judgement.
How it is calculated
| Serum K (mEq/L) | Estimated loss | K to add (mEq/L of fluid) | Max fluid rate (mL/kg/h) |
|---|---|---|---|
| 3.5–5 | Maintenance | 20 | 25 |
| 3.0–3.4 | Mild | 30 | 18 |
| 2.5–2.9 | Moderate | 40 | 12 |
| 2.0–2.4 | Severe | 60 | 8 |
| < 2 | Vital risk | 80 | 6 |
The potassium infusion rate should not exceed 0.5 mEq/kg/h in patients with normal renal function [1].
Worked example
K 2.7 mEq/L → 40 mEq/L; at 30 mL/h in a 10 kg dog = 0.12 mEq/kg/h.
Frequently asked questions
What is the maximum rate of potassium supplementation?
The cited guide states that the rate should not exceed 0.5 mEq/kg/h in patients with normal renal function [1].
How much KCl do I add to fluids for a potassium of 3.0?
For serum potassium 3.0–3.4 mEq/L the guide suggests 30 mEq per litre of fluid, with a maximum fluid rate of 18 mL/kg/h [1].
More electrolytes & acid–base calculators
References
For veterinary professionals. Information supports — never replaces — clinical judgement; always check the current product label and local regulations.