C-peptide ng/mL → nmol/L
Convert c-peptide from ng/mL to nmol/L
Sources last checked: 2026-11-03
C-peptide ng/mL → nmol/L
Convert c-peptide from ng/mL to nmol/L
Converts units only; reference ranges depend on the laboratory, the assay and the patient.
What is the C-peptide ng/mL → nmol/L?
C-peptide is cleaved from proinsulin in equimolar amounts with insulin and is reported in ng/mL in the USA, Turkey and many German-speaking labs, and in nmol/L or pmol/L in SI-based systems. This converter multiplies by 0.3311, derived from the molar mass of human C-peptide (3020.3 g/mol).
When to use it
- Reading diabetes classification studies or guidelines that quote C-peptide in nmol/L or pmol/L
- Comparing fasting or stimulated C-peptide across labs with different units
- Entering C-peptide into research formulas defined in SI units
When not to use it
- Urinary C-peptide or the urinary C-peptide/creatinine ratio, which use different units and denominators
- Converting insulin values — insulin has its own molar mass and is often reported in µU/mL
How it is calculated
C-peptide (nmol/L) = C-peptide (ng/mL) × 0.3311
Clinical pearls and limitations
- Converts units only; reference ranges depend on the laboratory, the assay and the patient.
- 1 ng/mL = 0.3311 nmol/L = 331.1 pmol/L.
- Many European labs report pmol/L; 1 nmol/L = 1000 pmol/L, so check whether the target is nmol/L or pmol/L.
- Fasting, random and stimulated (glucagon or mixed-meal) C-peptide are not interchangeable; the sampling condition matters more than the unit.
- C-peptide is cleared by the kidney; reduced kidney function raises the measured value independently of beta-cell secretion.
Frequently asked questions
How do I convert C-peptide from ng/mL to nmol/L?
Multiply by 0.3311. Example: 1.0 ng/mL × 0.3311 = 0.331 nmol/L; 3.0 ng/mL × 0.3311 = 0.993 nmol/L.
How do I get C-peptide in pmol/L from ng/mL?
Multiply by 331.1 (the nmol/L result × 1000). Example: 1.0 ng/mL = 331.1 pmol/L.
Why is the factor 0.3311?
ng/mL equals µg/L. Dividing by the molar mass of C-peptide (3020.3 g/mol) gives µmol/L, which × 1000 is nmol/L: 1000 ÷ 3020.3 ≈ 0.3311.
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-ng-ml-to-nmol-l">C-peptide ng/mL → nmol/L 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.