Potassium mmol to mg: multiply mmol by 39.1. 1 mmol of potassium = 39.1 mg = 1 mEq, so 20 mmol = 782 mg, 40 mmol = 1,564 mg and 90 mmol = 3,519 mg. For blood tests, potassium mmol/L × 3.91 = mg/dL (4.5 mmol/L = 17.6 mg/dL).
Potassium (K⁺) Calculator
Conversion settings
The calculator converts blood potassium (mmol/L ↔ mg/dL). For amounts in supplements, food and potassium chloride, use the mmol to mg chart below.
Potassium Conversion Factors
| Convert potassium | Formula | Example |
|---|---|---|
| mmol to mg | mg = mmol × 39.1 | 1 mmol = 39.1 mg |
| mmol to g | g = mmol × 0.0391 | 60 mmol = 2.35 g |
| mg to mmol | mmol = mg ÷ 39.1 | 3,510 mg = 89.8 mmol |
| g to mmol | mmol = g × 25.6 | 1 g = 25.6 mmol |
| mmol to mEq | mEq = mmol (charge 1) | 40 mmol = 40 mEq |
| mEq to mg | mg = mEq × 39.1 | 60 mEq = 2,346 mg |
| mmol/L to mg/dL (blood) | mg/dL = mmol/L × 3.91 | 4.0 mmol/L = 15.6 mg/dL |
| mg/dL to mmol/L (blood) | mmol/L = mg/dL ÷ 3.91 | 17.6 mg/dL = 4.5 mmol/L |
Potassium mmol to mg Chart
Use this chart to convert potassium mmol to mg for supplements, IV fluids and diet plans. Because potassium has a single charge, mmol and mEq are the same number.
| Potassium (mmol = mEq) | Potassium (mg) | Potassium (g) |
|---|---|---|
| 1 mmol (1 mEq) | 39 mg | 0.04 g |
| 2 mmol (2 mEq) | 78 mg | 0.08 g |
| 4 mmol (4 mEq) | 156 mg | 0.16 g |
| 5 mmol (5 mEq) | 195 mg | 0.20 g |
| 8 mmol (8 mEq) | 313 mg | 0.31 g |
| 10 mmol (10 mEq) | 391 mg | 0.39 g |
| 12 mmol (12 mEq) | 469 mg | 0.47 g |
| 15 mmol (15 mEq) | 586 mg | 0.59 g |
| 20 mmol (20 mEq) | 782 mg | 0.78 g |
| 25 mmol (25 mEq) | 977 mg | 0.98 g |
| 30 mmol (30 mEq) | 1,173 mg | 1.17 g |
| 40 mmol (40 mEq) | 1,564 mg | 1.56 g |
| 50 mmol (50 mEq) | 1,955 mg | 1.95 g |
| 60 mmol (60 mEq) | 2,346 mg | 2.35 g |
| 80 mmol (80 mEq) | 3,128 mg | 3.13 g |
| 90 mmol (90 mEq) | 3,519 mg | 3.52 g |
| 100 mmol (100 mEq) | 3,910 mg | 3.91 g |
90 mmol of potassium (about 3,500 mg) is close to the World Health Organization’s recommended adult intake of at least 3,510 mg a day. 1 g of potassium chloride (KCl) contains 13.4 mmol (524 mg) of potassium. For mg to mmol and KCl tables, see the potassium mg to mmol converter.
Potassium mmol/L to mg/dL Chart (Blood Potassium)
Blood potassium, shown as K on lab reports, is almost always reported in mmol/L (the same number as mEq/L). Multiply by 3.91 to get mg/dL. The meaning column is a general guide.
| Potassium (mmol/L = mEq/L) | Potassium (mg/dL) | Level (general guide) |
|---|---|---|
| 2.0 mmol/L | 7.8 mg/dL | Severely low |
| 2.5 mmol/L | 9.8 mg/dL | Low (hypokalemia) |
| 3.0 mmol/L | 11.7 mg/dL | Low (hypokalemia) |
| 3.1 mmol/L | 12.1 mg/dL | Low (hypokalemia) |
| 3.4 mmol/L | 13.3 mg/dL | Low (hypokalemia) |
| 3.5 mmol/L | 13.7 mg/dL | Normal |
| 3.7 mmol/L | 14.5 mg/dL | Normal |
| 3.9 mmol/L | 15.2 mg/dL | Normal |
| 4.0 mmol/L | 15.6 mg/dL | Normal |
| 4.2 mmol/L | 16.4 mg/dL | Normal |
| 4.3 mmol/L | 16.8 mg/dL | Normal |
| 4.5 mmol/L | 17.6 mg/dL | Normal |
| 4.7 mmol/L | 18.4 mg/dL | Normal |
| 5.0 mmol/L | 19.5 mg/dL | Normal |
| 5.3 mmol/L | 20.7 mg/dL | High (hyperkalemia) |
| 5.4 mmol/L | 21.1 mg/dL | High (hyperkalemia) |
| 5.5 mmol/L | 21.5 mg/dL | High (hyperkalemia) |
| 5.8 mmol/L | 22.7 mg/dL | High (hyperkalemia) |
| 6.0 mmol/L | 23.5 mg/dL | Very high: urgent |
| 6.5 mmol/L | 25.4 mg/dL | Very high: urgent |
| 7.0 mmol/L | 27.4 mg/dL | Very high: urgent |
Normal Potassium Levels (K mmol/L)
| Serum potassium | mmol/L (mEq/L) | mg/dL |
|---|---|---|
| Normal range (adults) | 3.5 – 5.0 | 13.7 – 19.6 |
| Low (hypokalemia) | below 3.5 | below 13.7 |
| High (hyperkalemia) | above 5.0 (some labs 5.5) | above 19.6 |
| Very high, needs urgent care | 6.0 or higher | 23.5 or higher |
Potassium levels such as 4.0, 4.2, 4.3 or 4.7 mmol/L are normal; 3.4 mmol/L is mildly low; 5.4–5.8 mmol/L is high; and 6.5 mmol/L is dangerously high because it can affect heart rhythm. Use the range on your own lab report and contact your doctor about abnormal results.
Potassium mmol vs mEq
For potassium, 1 mmol = 1 mEq, and mmol/L = mEq/L. So 60 mEq of potassium = 60 mmol = 2,346 mg. This is different for calcium and magnesium, which have a double charge.
Frequently Asked Questions
How do I convert potassium mmol to mg?
Multiply by 39.1. For example, 10 mmol × 39.1 = 391 mg.
How many mg is 1 mmol of potassium?
1 mmol of potassium = 39.1 mg.
How many mg is 20 mmol of potassium?
20 mmol = 782 mg of potassium.
How many mg is 40 mmol of potassium?
40 mmol = 1,564 mg of potassium.
How many mg is 90 mmol of potassium?
90 mmol = 3,519 mg (about 3.5 g) of potassium.
How do I convert potassium mmol/L to mg/dL?
Multiply by 3.91. For example, 4.5 mmol/L = 17.6 mg/dL and 5.8 mmol/L = 22.7 mg/dL.
Is potassium mmol the same as mEq?
Yes. Potassium has a charge of +1, so 1 mmol = 1 mEq.
Related: sodium mmol/L to mg/dL and all electrolyte and mineral conversions. In French, conversion potassium mmol en mg (× 39.1) and in German, Kalium mmol in mg, use the same factor.