30 ng/mL 25-hydroxyvitamin D to nmol/L
The answer, the conversion factor and where it comes from, a step-by-step manual calculation, and a companion table of nearby 25-hydroxyvitamin D values in both units. Mechanical unit conversion only. This page does not interpret the value clinically.
About 25-hydroxyvitamin D and these units
25-hydroxyvitamin D is the storage form of vitamin D measured to assess vitamin D status. 25-hydroxyvitamin D appears in ng/mL on US lab reports and in nmol/L on UK, Canadian, Australian, and most European lab reports.
Where the 2.496 conversion factor comes from
ng/mL is a mass-per-volume unit. nmol/L is a moles-per-volume (molar concentration) unit. To convert between them you need the molecular weight of the substance, because that determines how many moles of it fit into a given mass.
For 25-hydroxyvitamin D, the reference molecular weight is 400.64 g/mol. Working through the unit algebra:
- The factor is fixed by the molecular weight (400.64 g/mol) together with the mass and volume prefixes of the two units, since a molar concentration counts molecules and a mass concentration weighs them.
- For 25-hydroxyvitamin D this works out to
2.496nmol/L per ng/mL (multiply ng/mL by 2.496 to get nmol/L). - The inverse (nmol/L → ng/mL) is
0.4006.
Step-by-step: converting 30 ng/mL of 25-hydroxyvitamin D by hand
- Start with the lab value:
30 ng/mL. - Look up the conversion factor for 25-hydroxyvitamin D:
2.496 nmol/L per ng/mL. - Multiply:
30 × 2.496 = 74.88. - Attach the SI unit:
74.88 nmol/L.
Inverse check: 74.88 nmol/L ÷ 2.496 = 30 ng/mL ✓.
Companion conversions for nearby 25-hydroxyvitamin D values
If your lab reported a number close to but not exactly 30 ng/mL, the table below covers the surrounding range so you don't need to re-run the arithmetic.
| ng/mL | nmol/L |
|---|---|
| 8 | 19.968 |
| 15 | 37.44 |
| 23 | 57.408 |
| 27 | 67.392 |
| 30 | 74.88 |
| 33 | 82.368 |
| 38 | 94.848 |
| 45 | 112.32 |
| 53 | 132.29 |
| 60 | 149.76 |
| 75 | 187.2 |
| 90 | 224.64 |
A note on precision
Clinical chemistry assays for 25-hydroxyvitamin D are typically precise to two or three significant figures. The exact factor 2.496 is itself a rounded number, and the molecular weight that produces it (400.64 g/mol) is conventionally rounded. So while the calculator displays 74.88 nmol/L for 30 ng/mL, reporting more decimal places than your original measurement supports is false precision.
Common questions
What is 30 ng/mL 25-hydroxyvitamin D in nmol/L?
30 ng/mL of 25-hydroxyvitamin D equals 74.88 nmol/L. The conversion factor for 25-hydroxyvitamin D is 2.496 (multiply ng/mL by 2.496 to get nmol/L).
How do I convert ng/mL to nmol/L for 25-hydroxyvitamin D?
25-hydroxyvitamin D has a conversion factor of 2.496. Formula: 30 ng/mL × 2.496 = 74.88 nmol/L. Inverse: 74.88 nmol/L ÷ 2.496 = 30 ng/mL.
Why does 25-hydroxyvitamin D have a different conversion factor than other biomarkers?
Each biomarker's ng/mL ↔ nmol/L factor is set by its molecular weight, because nmol/L is a molar concentration. For 25-hydroxyvitamin D, the reference molecular weight is 400.64 g/mol, which gives a factor of 2.496.
Where is ng/mL used and where is nmol/L used?
25-hydroxyvitamin D appears in ng/mL on US lab reports and in nmol/L on UK, Canadian, Australian, and most European lab reports.
How precise should I report the converted value?
Lab assays for 25-hydroxyvitamin D are typically precise to about two or three significant figures. Reporting more decimal places than your original measurement supports is false precision. For a reading of 30 ng/mL, 74.88 nmol/L is appropriate; further decimals are not.
Related conversions and reference
- Full blood test unit converter: convert any value for 50+ biomarkers in either direction.
- HbA1c ↔ average glucose converter: separate page for the HbA1c (% / mmol/mol) ↔ eAG conversion.
- Cholesterol ratio calculator: total/HDL and LDL/HDL ratios.
Track 25-hydroxyvitamin D over time, in either unit system
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