Magnesium conversion: blood magnesium (Mg) in mmol/L × 2.43 = mg/dL. For supplements and medicines, 1 mmol of magnesium = 24.3 mg, so 4 mmol = 97 mg and 1.65 mmol = 40 mg. Example: serum magnesium 0.85 mmol/L = 2.07 mg/dL = 1.7 mEq/L.
Magnesium (Mg²⁺) Calculator
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Magnesium Conversion Factors
Magnesium (chemical symbol Mg) has an atomic mass of 24.305 and a charge of +2, which gives these factors. On lab reports and in searches, “Mg mmol/L to mg/dL” means magnesium; don’t confuse the symbol Mg with the unit mg.
| Convert magnesium | Formula | Example |
|---|---|---|
| mmol/L to mg/dL | mg/dL = mmol/L × 2.431 | 0.9 mmol/L = 2.19 mg/dL |
| mg/dL to mmol/L | mmol/L = mg/dL ÷ 2.431 (or × 0.411) | 2.0 mg/dL = 0.82 mmol/L |
| mmol/L to mg/L | mg/L = mmol/L × 24.31 | 0.9 mmol/L = 21.9 mg/L |
| mmol/L to mEq/L | mEq/L = mmol/L × 2 | 0.9 mmol/L = 1.8 mEq/L |
| mg/dL to mEq/L | mEq/L = mg/dL ÷ 1.215 (or × 0.823) | 2.0 mg/dL = 1.65 mEq/L |
| mmol to mg (amount) | mg = mmol × 24.3 | 10 mmol = 243 mg |
| mg to mmol (amount) | mmol = mg ÷ 24.3 | 400 mg = 16.5 mmol |
| mEq to mg (amount) | mg = mEq × 12.15 | 10 mEq = 121.5 mg |
Magnesium mmol/L to mg/dL Chart
| Magnesium (mmol/L) | Magnesium (mg/dL) | Magnesium (mEq/L) |
|---|---|---|
| 0.30 mmol/L | 0.73 mg/dL | 0.6 mEq/L |
| 0.40 mmol/L | 0.97 mg/dL | 0.8 mEq/L |
| 0.50 mmol/L | 1.22 mg/dL | 1.0 mEq/L |
| 0.60 mmol/L | 1.46 mg/dL | 1.2 mEq/L |
| 0.65 mmol/L | 1.58 mg/dL | 1.3 mEq/L |
| 0.70 mmol/L | 1.70 mg/dL | 1.4 mEq/L |
| 0.75 mmol/L | 1.82 mg/dL | 1.5 mEq/L |
| 0.80 mmol/L | 1.94 mg/dL | 1.6 mEq/L |
| 0.85 mmol/L | 2.07 mg/dL | 1.7 mEq/L |
| 0.90 mmol/L | 2.19 mg/dL | 1.8 mEq/L |
| 0.95 mmol/L | 2.31 mg/dL | 1.9 mEq/L |
| 1.00 mmol/L | 2.43 mg/dL | 2.0 mEq/L |
| 1.10 mmol/L | 2.67 mg/dL | 2.2 mEq/L |
| 1.20 mmol/L | 2.92 mg/dL | 2.4 mEq/L |
| 1.50 mmol/L | 3.65 mg/dL | 3.0 mEq/L |
| 2.00 mmol/L | 4.86 mg/dL | 4.0 mEq/L |
| 2.50 mmol/L | 6.08 mg/dL | 5.0 mEq/L |
| 3.00 mmol/L | 7.29 mg/dL | 6.0 mEq/L |
Blood magnesium is normally below about 1.0 mmol/L, so a value such as 2.4 or 3.6 mmol/L is either very high or belongs to a different test. Check the test name before converting; for glucose or cholesterol use the main mmol/L to mg/dL converter.
Magnesium mg/dL to mmol/L Conversion
To convert magnesium from mg/dL to mmol/L, divide by 2.431. A result of 1.5 mg/dL is 0.62 mmol/L, which is low. For a dedicated reverse tool, use the magnesium mg/dL to mmol/L converter.
| Magnesium (mg/dL) | Magnesium (mmol/L) | Magnesium (mEq/L) |
|---|---|---|
| 1.0 mg/dL | 0.41 mmol/L | 0.82 mEq/L |
| 1.2 mg/dL | 0.49 mmol/L | 0.99 mEq/L |
| 1.5 mg/dL | 0.62 mmol/L | 1.23 mEq/L |
| 1.7 mg/dL | 0.70 mmol/L | 1.40 mEq/L |
| 1.8 mg/dL | 0.74 mmol/L | 1.48 mEq/L |
| 2.0 mg/dL | 0.82 mmol/L | 1.65 mEq/L |
| 2.2 mg/dL | 0.91 mmol/L | 1.81 mEq/L |
| 2.4 mg/dL | 0.99 mmol/L | 1.97 mEq/L |
| 2.6 mg/dL | 1.07 mmol/L | 2.14 mEq/L |
| 3.0 mg/dL | 1.23 mmol/L | 2.47 mEq/L |
| 4.0 mg/dL | 1.65 mmol/L | 3.29 mEq/L |
| 5.0 mg/dL | 2.06 mmol/L | 4.11 mEq/L |
Normal Serum Magnesium Levels (mmol/L and mg/dL)
| Serum magnesium | mmol/L | mg/dL | mEq/L |
|---|---|---|---|
| Normal range (adults) | 0.70 – 1.00 | 1.7 – 2.4 | 1.4 – 2.0 |
| Low magnesium (hypomagnesemia) | below 0.70 | below 1.7 | below 1.4 |
| Severe low magnesium | below 0.50 | below 1.2 | below 1.0 |
| High magnesium (hypermagnesemia) | above 1.00 | above 2.4 | above 2.0 |
Reference ranges vary slightly between labs (some use 0.75–0.95 mmol/L). Low magnesium is common with diuretics, proton-pump inhibitors, diarrhoea and alcohol use; high magnesium is uncommon and usually linked to kidney problems or too much magnesium medicine. Discuss your result with your doctor.
Magnesium mmol to mg (Supplements and Medicines)
Supplement and medicine labels often give magnesium in mmol. To convert magnesium mmol in mg, multiply by 24.3. For example, a tablet with 1.65 mmol of magnesium contains 40.1 mg of elemental magnesium, and 4 mmol = 97.2 mg.
| Magnesium (mmol) | Elemental magnesium (mg) | Magnesium (mEq) |
|---|---|---|
| 1 mmol | 24.3 mg | 2 mEq |
| 1.65 mmol | 40.1 mg | 3.3 mEq |
| 2 mmol | 48.6 mg | 4 mEq |
| 3 mmol | 72.9 mg | 6 mEq |
| 4 mmol | 97.2 mg | 8 mEq |
| 5 mmol | 121.5 mg | 10 mEq |
| 8 mmol | 194.4 mg | 16 mEq |
| 10 mmol | 243.1 mg | 20 mEq |
| 12.3 mmol | 299.0 mg | 24.6 mEq |
| 15 mmol | 364.6 mg | 30 mEq |
| 20 mmol | 486.1 mg | 40 mEq |
| 25 mmol | 607.6 mg | 50 mEq |
Magnesium mg to mmol
To convert magnesium mg to mmol, divide by 24.3. 1 g (1,000 mg) of elemental magnesium = 41.1 mmol.
| Magnesium (mg) | Magnesium (mmol) |
|---|---|
| 40 mg | 1.65 mmol |
| 50 mg | 2.06 mmol |
| 100 mg | 4.11 mmol |
| 120 mg | 4.94 mmol |
| 150 mg | 6.17 mmol |
| 200 mg | 8.23 mmol |
| 250 mg | 10.29 mmol |
| 300 mg | 12.34 mmol |
| 350 mg | 14.40 mmol |
| 400 mg | 16.46 mmol |
| 500 mg | 20.57 mmol |
| 1,000 mg | 41.14 mmol |
| 2,000 mg | 82.29 mmol |
Magnesium salts are different. The weight of a magnesium compound is not all magnesium. For example, 2 g of magnesium sulfate heptahydrate (the usual IV dose) contains about 8 mmol of magnesium (197 mg), and 1 g of magnesium oxide contains about 24.8 mmol (603 mg). Always check whether a label gives “elemental magnesium” or the weight of the salt.
Mg/mmol vs mg/dL: Not the Same Kind of Unit
Some searches ask how to convert mg/mmol to mg/dL. mg/mmol is a ratio (for example the urine albumin-to-creatinine ratio, in mg of albumin per mmol of creatinine), not a blood concentration, so it cannot be converted to mg/dL. If your report shows “Mg” (magnesium) in mmol/L, use the calculator above.
Frequently Asked Questions
How do I convert magnesium mmol/L to mg/dL?
Multiply by 2.431. For example, 0.8 mmol/L × 2.431 = 1.94 mg/dL.
What is the magnesium conversion factor?
1 mmol/L = 2.431 mg/dL = 2 mEq/L. To go from mg/dL to mmol/L, multiply by 0.411.
How many mg is 4 mmol of magnesium?
4 mmol × 24.3 = 97.2 mg of magnesium.
How many mg is 1.65 mmol of magnesium?
1.65 mmol × 24.3 = 40.1 mg, about 40 mg of elemental magnesium.
How many mg is 10 mmol of magnesium?
10 mmol = 243 mg. 5 mmol = 121.5 mg and 20 mmol = 486 mg.
What is a normal magnesium level in mmol/L and mg/dL?
About 0.70–1.00 mmol/L, which is 1.7–2.4 mg/dL or 1.4–2.0 mEq/L.
How do I convert magnesium mEq to mg?
Multiply mEq by 12.15. Magnesium has a charge of +2, so 1 mmol = 2 mEq and 1 mEq = 12.15 mg.
How do I convert mmol to mg for any substance?
Multiply mmol by the molar mass in g/mol. For magnesium the molar mass is 24.3, so mg = mmol × 24.3.
Related: calcium mmol/L to mg/dL, potassium mg to mmol and all electrolyte and mineral conversions. In Italian: conversione magnesio mmol/L in mg/dL uses the same factor (× 2.431).