The normal range for potassium in the blood is between 3.6 and 5.2 millimoles per liter, according to Healthline. This sometimes varies depending on the laboratory that performs the test, but the doctor uses the range marked on the results to make informed recommendations.
The potassium level in the blood is strictly regulated by the body, and levels outside the normal range are potentially dangerous. Too little potassium in the blood is known as hypokalemia, and some common causes include chronic diarrhea and vomiting. Hyperkalemia is elevated blood potassium and is often caused by an excess of potassium in the diet.