Ionized Calcium unit converter
Convert ionized calcium between mg/dL and mmol/L. Type in either box. The factors come from our catalog and are checked by code.
AI-verified against cited sources. Awaiting expert reviewLast reviewed 2026-10-03
1 mg/dL = 0.2495 mmol/L. Nothing you type here leaves your browser.
The conversion
- 1 mg/dL = 0.2495 mmol/LFrom mg/dL to mmol/L: divide by 4.008. Back again: multiply by 4.008.
Mass and molar units are linked by the molecular weight: 40.08 g/mol (calcium (Ca), atomic weight). Source: PubChem, National Library of Medicine.
Common values
From zero to about twice the usual upper limit, plus the usual limits themselves.
| mg/dL | mmol/L |
|---|---|
| 2 | 0.5 |
| 4 | 1 |
| 4.57 | 1.14 |
| 5.43 | 1.35 |
| 6 | 1.5 |
| 8 | 2 |
| 10 | 2.5 |
Usual ranges in each unit
What labs print as the reference range, by who was tested. Sources for each range are on the Ionized Calcium page.
| Who | mg/dL | mmol/L |
|---|---|---|
| 24–97 | 4.57–5.43 | 1.14–1.35 |
| 3–23 | 4.83–5.52 | 1.21–1.38 |
| 2 | 4.87–5.67 | 1.22–1.41 |
| 1 | 5.04–5.84 | 1.26–1.46 |
| 0.038–0 | 5.21–5.99 | 1.3–1.49 |