Magnesium mg/dL → mmol/L
Convert magnesium from mg/dL to mmol/L
Sources last checked: 2026-11-03
Magnesium mg/dL → mmol/L
Convert magnesium from mg/dL to mmol/L
Converts units only; reference ranges depend on the laboratory, the assay and the patient.
What is the Magnesium mg/dL → mmol/L?
This converter turns total serum magnesium from mg/dL — the unit in Turkey, the USA and some other labs — into mmol/L, which many labs in Germany, Austria, the UK and Scandinavia use. It multiplies by 0.4114, i.e. 10 ÷ the atomic mass of magnesium (24.305 g/mol).
When to use it
- Comparing a mg/dL magnesium result with European reports or guidelines in mmol/L
- Interpreting literature on electrolyte replacement written in SI units
- Exam questions that switch between unit systems
When not to use it
- Results in mEq/L — that is a third unit; 1 mmol/L of Mg²⁺ equals 2 mEq/L
- Ionised magnesium, which is measured separately and is not derivable from total magnesium by a factor
- Judging deficiency or toxicity: reference ranges depend on the laboratory
How it is calculated
Magnesium (mmol/L) = magnesium (mg/dL) × 0.4114
Clinical pearls and limitations
- Converts units only; reference ranges depend on the laboratory, the assay and the patient.
- Magnesium is divalent: mEq/L = mmol/L × 2. Mixing up mmol/L and mEq/L doubles or halves the apparent value.
- Serum magnesium reflects only a small fraction of total body magnesium, so a normal value does not exclude depletion.
- Haemolysis raises measured magnesium, because red cells contain more magnesium than plasma.
- Hypomagnesaemia often coexists with hypokalaemia and hypocalcaemia; check related electrolytes in the same unit system.
Frequently asked questions
How do I convert magnesium from mg/dL to mmol/L?
Multiply by 0.4114. For example, 2 mg/dL × 0.4114 = 0.823, about 0.82 mmol/L.
What is 1.5 mg/dL magnesium in mmol/L?
1.5 × 0.4114 = 0.617, about 0.62 mmol/L.
How do I get magnesium in mEq/L from mg/dL?
Convert to mmol/L and double it: 2 mg/dL → 0.82 mmol/L → about 1.65 mEq/L (2 × 0.8228).
Evidence and guidelines
Have a follow-up question?
Medelix answers clinical questions from current guidelines and studies — every statement with its source.
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<p><a href="https://medelix.ai/en/calculators/magnesium-mg-dl-to-mmol-l">Magnesium mg/dL → mmol/L calculator by Medelix</a></p>For healthcare professionals and medical students. These tools support, and do not replace, clinical judgement. Always check results against the original source and your local protocols.