nmol/L to ng/mL Converter

Is “nM” the Same as “nmol/L”?

Yes. nM (nanomolar) and nmol/L (nanomoles per litre) are exactly the same unit – “nM” is simply the chemistry shorthand for a molar concentration of one nanomole per litre, and lab reports, textbooks and research papers use the two interchangeably. So if you’re searching for “nm to ng/ml,” “convert nm to ng/ml,” or “ng/ml to nm,” you’re asking the identical question as “nmol/l to ng/ml” – use the same formula and the same calculator above, and enter your value exactly as shown.

The nmol/L to ng/mL Formula

Converting a molar concentration (nmol/L) into a mass concentration (ng/mL) requires the molecule’s molecular weight (MW), measured in grams per mole (g/mol):

ng/mL to nmol/L (the reverse direction)

The molecular weight is the only variable that changes between molecules – it’s why there’s no single “nmol/L to ng/mL” conversion factor the way there is for, say, milligrams to grams. A heavier molecule (higher MW) needs more mass to represent the same molar concentration, so its ng/mL value is proportionally larger for the same nmol/L reading.

nmol/L to ng/mL Conversion Chart by Molecule

*Vitamin A is usually reported in µmol/L (micromoles/L), shown here for reference – use the “Custom molecular weight” option if your report uses a unit the calculator doesn’t list by name. Every molecule above (plus Vitamin E, Folate, Melatonin, T3 and Androstenedione) is available in the calculator’s molecule dropdown with its molecular weight cross-checked against PubChem.

Vitamin D: nmol/L to ng/mL

Vitamin D (25-hydroxyvitamin D, or 25-OH-D) is by far the most commonly searched molecule on this page, and outside the US it’s almost always reported in nmol/L rather than ng/mL. The molecular weight of 25-hydroxyvitamin D is 400.64 g/mol, so:

*Interpretation bands vary by lab and guideline (Endocrine Society vs. Institute of Medicine cut-offs differ slightly) – always read your result against the reference range printed on your own lab report, not a generic table, and discuss it with your doctor.

Testosterone: nmol/L to ng/mL

Total testosterone has a molecular weight of 288.42 g/mol. Typical adult male total testosterone ranges from roughly 10-30 nmol/L; typical adult female ranges from roughly 0.5-2.4 nmol/L, though exact reference ranges vary by lab, age and assay method.

This converts total testosterone only. Free testosterone and bioavailable testosterone depend on SHBG and albumin binding and need a different (non-unit) calculation, not a simple molecular-weight conversion.

Cortisol, Progesterone, and Estradiol

These three steroid hormones are also commonly reported in nmol/L and each has its own molecular weight, so each needs its own conversion:

Cortisol follows a daily rhythm (highest in the morning, lowest at night), so timing matters more for interpreting the result than for the unit conversion itself. Progesterone and estradiol both vary substantially across the menstrual cycle and by pregnancy stage – always compare your result to the reference range for your specific cycle phase or trimester, not a single flat number.

pmol/L to ng/mL (and Other Related Units)

Some labs – especially for estradiol, vitamin B12, aldosterone and free hormones – report results in pmol/L (picomoles per litre) instead of nmol/L. The relationship is simple: 1 nmol/L = 1,000 pmol/L, so a pmol/L value is a thousand times smaller than the same concentration expressed in nmol/L.

Rather than converting pmol/L to nmol/L by hand first, use the “Molar unit” dropdown in the calculator at the top of this page – switch it to pmol/L, enter your value as-is, and it applies the extra factor of 1,000 automatically. A few labs also use mmol/L (millimoles per litre, 1,000 times larger than nmol/L) for very high-concentration analytes; if you have an mmol/L value, convert it to nmol/L first by multiplying by 1,000,000, then use the calculator normally.

ng/mL to nmol/L (Reverse Conversion)

Going the other direction – from a mass concentration back to a molar one – uses the same molecular weight, just rearranged: nmol/L = (ng/mL × 1,000) ÷ MW. This is common when a US lab reports a result in ng/mL but you need to compare it to an international reference range given in nmol/L (or vice versa). Use the “Direction” dropdown in the calculator above to switch to ng/mL → nmol/L (or pmol/L) – the molecule and molecular weight you’ve already selected carry over automatically.

How to Use This Converter

Select the molecule your lab result is for from the “Molecule” dropdown – this sets the correct molecular weight automatically. If your molecule isn’t listed, choose “Custom molecular weight” and enter the MW from your lab’s reference sheet or a source like PubChem.

Pick “nmol/L” or “pmol/L” depending on which unit your report actually uses – don’t assume; check the report. Enter your value, and the result, the per-molecule reference table, and the quick-value chips all update instantly without reloading the page.

Frequently Asked Questions