Potassium Salt (mEq, mmol, mg) Converter
Potassium Salt (mEq, mmol, mg) Converter
Convert a potassium salt dose in milligrams to mmol (equal to mEq for this monovalent ion), across the common oral salts.
Potassium Salt (mEq, mmol, mg) Converter
mg → mmolPotassium chloride 600 mg (13.4 mmol per g)
Formula
- mmol per gram
- fixed by each salt's molecular weight and the number of potassium ions it releases
- mEq
- numerically identical to mmol for potassium, because potassium is monovalent (charge +1)
Worked example
Potassium chloride 600 mg (13.4 mmol per g)
600 ÷ 1000 = 0.6 g
0.6 × 13.4 = 8.04 mmol K⁺
mmol per gram by salt
| Salt | mmol K⁺ per gram | Typical use |
|---|---|---|
| Potassium chloride | 13.4 | First-line oral or IV replacement |
| Potassium citrate | 9.26 | Renal stone prevention, urine alkalinisation |
| Potassium gluconate | 4.3 | Oral supplementation where chloride is undesirable |
| Potassium bicarbonate | 10 | Combined potassium and alkali replacement |
mmol, mEq, and why they are the same number here
For potassium, mmol and mEq are numerically identical because potassium is monovalent — a single positive charge per ion. This is the single most useful fact to carry into any potassium calculation, and it is not true of calcium or magnesium, both divalent, where 1 mmol equals 2 mEq. A dose expressed in mmol of potassium can therefore be read directly as mEq without conversion.
A 600 mg dose of potassium chloride provides about 8 mmol; the common 8 mmol modified-release tablet found in most formularies is, unsurprisingly, close to 600 mg of the salt. Oral replacement of 40 to 60 mmol typically raises serum potassium by roughly 1 to 1.5 mmol/L, though this relationship is genuinely unreliable in practice, because more than 98% of total body potassium is intracellular and the serum level is a poor proxy for total body stores.
One clinical pattern is worth stating plainly: hypokalaemia that resists replacement is usually caused by unrecognised hypomagnesaemia. Magnesium is required for the renal outer medullary potassium channel (ROMK) to close properly; without adequate magnesium the channel stays open and the kidney continues excreting potassium as fast as it is replaced. Checking and correcting magnesium alongside potassium — rather than simply escalating the potassium dose — is what actually resolves refractory hypokalaemia.
Frequently asked questions
Is mmol the same as mEq for potassium?
Yes, exactly. Potassium is monovalent, so 1 mmol equals 1 mEq. This is not true for divalent ions such as calcium or magnesium, where 1 mmol equals 2 mEq.
How much potassium is in a 600 mg potassium chloride tablet?
About 8 mmol (8 mEq). Potassium chloride provides 13.4 mmol per gram of salt.
How much does oral potassium replacement raise serum potassium?
Roughly 1 to 1.5 mmol/L for 40 to 60 mmol given, though this is unreliable — most potassium is intracellular, so the serum level is only a rough guide to total body stores.
Why does hypokalaemia not respond to potassium replacement?
Refractory hypokalaemia is usually caused by hypomagnesaemia. Magnesium is needed to close the renal outer medullary potassium channel, and without correcting it the kidney continues losing potassium regardless of how much is replaced.
Related calculators
References
- Gennari FJ. Hypokalemia. N Engl J Med. 1998;339(7):451–458.
- Huang CL, Kuo E. Mechanism of hypokalemia in magnesium deficiency. J Am Soc Nephrol. 2007;18(10):2649–2652.
Medical Disclaimer: The tools and content provided here are for educational and reference purposes only. They are not intended to substitute for professional medical advice, diagnosis, or treatment. Clinical decisions should always be based on the comprehensive assessment of a qualified healthcare professional.