Calcium mmol/L to mg/dL Converter
Instantly and accurately convert blood calcium levels between millimoles per litre (mmol/L) and milligrams per decilitre (mg/dL). Free, medical-grade, and easy to use.
Convert Your Calcium Levels
Enter your blood calcium value in either unit below. The calculator will instantly compute the equivalent value in the other unit using the standard medical conversion factor.
Calcium Unit Converter
Type a value in either field to see the real-time conversion
Millimoles per litre
Milligrams per decilitre
Conversion Result
Based on atomic weight of calcium (40.08 g/mol)
Enter a value in either the mmol/L or mg/dL field to see your instant conversion result and breakdown.
Normal Blood Calcium Ranges
Standard reference ranges for blood calcium levels in adults. Note that reference ranges may vary slightly between different laboratories.
| Calcium Type | Normal Range (mmol/L) | Normal Range (mg/dL) | Primary Use |
|---|---|---|---|
| Total Calcium | 2.20 – 2.60 | 8.8 – 10.4 | Routine blood panels (CMP) |
| Ionised Calcium | 1.10 – 1.30 | 4.4 – 5.2 | Critical care, albumin abnormalities |
| Corrected Calcium | 2.20 – 2.60 | 8.8 – 10.4 | Adjusted for abnormal albumin levels |
Calcium Conversion FAQ
Everything you need to know about blood calcium units, conversion, and test interpretation.
To convert calcium from mmol/L to mg/dL, multiply the value in mmol/L by 4.008. This conversion factor is derived from the atomic weight of calcium (40.08 g/mol). For example, 2.5 mmol/L × 4.008 = 10.02 mg/dL.
The normal reference range for total blood calcium is typically 2.2 to 2.6 mmol/L, which is equivalent to 8.8 to 10.4 mg/dL. For ionised (active) calcium, the normal range is approximately 1.1 to 1.3 mmol/L (4.4 to 5.2 mg/dL). Always refer to the specific reference ranges provided by your testing laboratory.
The use of different units is based on regional medical conventions. The UK, Canada, Australia, and most of Europe use the International System of Units (SI), which measures concentration in mmol/L. The United States and a few other countries traditionally use conventional units, measuring concentration in mg/dL.
Yes. About 40–45% of blood calcium is bound to the protein albumin. If your albumin levels are abnormally low or high, your ‘total’ calcium result may appear falsely low or high. In these cases, doctors often calculate ‘corrected calcium’ or directly measure ‘ionised calcium’ for a more accurate clinical assessment.