Calcium mg/dL → mmol/L
Convert total or ionised calcium from mg/dL to mmol/L
Sources last checked: 2026-10-27
Calcium mg/dL → mmol/L
Convert total or ionised calcium from mg/dL to mmol/L
Converts units only. Total calcium depends on albumin; ionised calcium is preferred when protein binding is abnormal.
What is the Calcium mg/dL → mmol/L?
Turkish and US laboratories, and much of the older literature, report calcium in mg/dL; most European laboratories and guidelines use mmol/L. With a molar mass of 40.08 g/mol, 1 mg/dL equals 0.2495 mmol/L, so dividing by 4.008 (about 4) gives mmol/L.
When to use it
- Reading a Turkish or US result against European reference ranges or guideline thresholds
- Hypercalcaemia severity bands given in mmol/L (e.g. 3.0 and 3.5 mmol/L)
- Comparing results across labs and literature
When not to use it
- Ionised versus total calcium — the conversion does not turn one into the other
- Urinary calcium reported per 24 h, which also needs volume
How it is calculated
Calcium (mmol/L) = calcium (mg/dL) ÷ 4.008 (molar mass 40.08 g/mol; the AMA table rounds the factor to 0.25)
Clinical pearls and limitations
- Converts units only. Total calcium depends on albumin; ionised calcium is preferred when protein binding is abnormal.
- 8.8–10.4 mg/dL ≈ 2.2–2.6 mmol/L (typical total calcium range).
- 12 mg/dL ≈ 3.0 mmol/L and 14 mg/dL ≈ 3.5 mmol/L — the common moderate and severe hypercalcaemia thresholds.
- Correct for albumin in mg/dL first, then convert, or use ionised calcium.
Frequently asked questions
How do I convert calcium from mg/dL to mmol/L?
Divide by 4.008 (≈ 4). Example: 9.6 mg/dL = 2.40 mmol/L.
What is 10 mg/dL calcium in mmol/L?
About 2.50 mmol/L.
Do I need to correct calcium for albumin?
Total calcium falls with low albumin; use the corrected calcium calculator or measure ionised calcium.
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/calcium-mg-dl-to-mmol-l">Calcium 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.