Potassium: normal range and what it means
Short answer: The normal potassium range is 3.5 – 5.1 mmol/L for adults. Labs differ a little, so also check the range printed on your report.
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Where does your potassium sit?
Same number as mEq/L.
Your result
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Information, not a diagnosis. Talk to a doctor about your result, and sooner if you feel unwell.
An electrolyte critical for heart and muscle function.
Normal range
Adult reference range.
- Low< 3.5 mmol/L
- Normal3.5 – 5.1 mmol/L
- High≥ 5.1 mmol/L
What it measures
The main electrolyte inside your cells, and the one your heart rhythm depends on most. Both high and low values matter, and both can be dangerous.
What moves it
Kidney function, some blood-pressure medications, and sample handling — a squeezed or slow draw leaks potassium from cells and falsely raises the result.
How to bring it into range
A clenched fist or a difficult draw can falsely raise it, so an odd result is usually repeated before anyone acts.
How fast it responds
Hours to days.
Also reported as: k · serum potassium
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Common questions
- What is the normal potassium range?
- The normal potassium range is 3.5 – 5.1 mmol/L for adults. Labs differ a little, so also check the range printed on your report.
- What does a high Potassium mean?
- A value above the reference band means Potassium is outside the range typical for a healthy adult. A single reading is rarely conclusive on its own — what matters is the trend across draws and the other markers around it, which is why HealthOS reads the whole panel together rather than one number at a time.
- How do I improve my Potassium?
- A clenched fist or a difficult draw can falsely raise it, so an odd result is usually repeated before anyone acts.
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Reference ranges are general-population guidance compiled from common clinical laboratories, not a diagnosis. Lab-to-lab ranges differ. Always read your results with your doctor.