C-peptide nmol/L → ng/mL
Convert c-peptide from nmol/L to ng/mL
Sources last checked: 2026-11-03
C-peptide nmol/L → ng/mL
Convert c-peptide from nmol/L to ng/mL
Converts units only; reference ranges depend on the laboratory, the assay and the patient.
What is the C-peptide nmol/L → ng/mL?
This converter changes C-peptide from nmol/L, the SI unit used in much of the European literature, into ng/mL, the conventional unit used in the USA, Turkey and many German-speaking laboratories. It divides by 0.3311, the factor that follows from the molar mass of human C-peptide (3020.3 g/mol).
When to use it
- Interpreting a C-peptide in nmol/L from a study or foreign report when the local lab reports ng/mL
- Comparing serial values measured in labs with different units
- Translating thresholds from SI-based research into the unit used locally — with the caveats below
When not to use it
- Results reported in pmol/L — divide by 1000 first to get nmol/L, or the result is 1000-fold too high
- Insulin or proinsulin, which have different molar masses
How it is calculated
C-peptide (ng/mL) = C-peptide (nmol/L) ÷ 0.3311
Clinical pearls and limitations
- Converts units only; reference ranges depend on the laboratory, the assay and the patient.
- 1 nmol/L ≈ 3.02 ng/mL.
- A value labelled pmol/L that looks a thousand times too large is the most common C-peptide unit error.
- Assays are standardised less tightly than many routine analytes; method-specific reference intervals still apply.
- Interpret together with simultaneous glucose: a C-peptide without a paired glucose is hard to read.
Frequently asked questions
How do I convert C-peptide from nmol/L to ng/mL?
Divide by 0.3311. Example: 0.5 nmol/L ÷ 0.3311 = 1.51 ng/mL.
How do I convert C-peptide from pmol/L to ng/mL?
Divide pmol/L by 1000 to get nmol/L, then divide by 0.3311. Example: 600 pmol/L = 0.6 nmol/L ÷ 0.3311 = 1.81 ng/mL.
Is C-peptide in nmol/L the same as insulin in nmol/L?
They are secreted in equimolar amounts, but their clearance differs, so measured molar concentrations in blood are not equal.
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/c-peptide-nmol-l-to-ng-ml">C-peptide nmol/L → ng/mL 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.