HbA1c mmol/mol → %
Convert HbA1c from IFCC mmol/mol to NGSP/DCCT percent
- IFCC–NGSP master equation
Sources last checked: 2026-10-13
HbA1c mmol/mol → %
Convert HbA1c from IFCC mmol/mol to NGSP/DCCT percent
Converts between reporting units only. HbA1c is unreliable with altered red cell lifespan (haemolysis, recent transfusion, iron deficiency), some haemoglobin variants and advanced CKD.
What is the HbA1c mmol/mol → %?
This converter turns an IFCC HbA1c result in mmol/mol into the DCCT/NGSP percentage still used in many trials, textbooks and patient materials. It applies the IFCC–NGSP master equation published by NGSP, which is grounded in the IFCC reference system (Hoelzel et al., 2004).
When to use it
- Comparing a European mmol/mol result with targets expressed in %
- Explaining results to patients familiar with percentages
- Reading older literature
When not to use it
- When HbA1c is invalid because of altered red cell turnover or variant haemoglobins
- Estimating average glucose — use an eAG calculator
How it is calculated
HbA1c (%, NGSP) = 0.09148 × HbA1c (mmol/mol, IFCC) + 2.152
Clinical pearls and limitations
- Converts between reporting units only. HbA1c is unreliable with altered red cell lifespan (haemolysis, recent transfusion, iron deficiency), some haemoglobin variants and advanced CKD.
- 48 mmol/mol = 6.5 %; 53 = 7.0 %; 64 = 8.0 %; 75 = 9.0 %.
- A change of 1 % corresponds to about 11 mmol/mol.
- Some countries print both units; check which one a target refers to.
Frequently asked questions
How do I convert HbA1c from mmol/mol to %?
% = 0.09148 × mmol/mol + 2.152. Example: 53 mmol/mol → 7.0 %.
What is 42 mmol/mol in %?
About 6.0 %.
Is 48 mmol/mol diabetes?
48 mmol/mol (6.5 %) is the WHO diagnostic threshold when confirmed and measured with a standardised method.
Evidence and guidelines
- Primary source: NGSP. IFCC Standardization of HbA1c — IFCC–NGSP master equation: NGSP (%) = 0.09148 × IFCC (mmol/mol) + 2.152; IFCC = 10.93 × NGSP − 23.50.
- Hoelzel W et al. IFCC reference system for measurement of hemoglobin A1c in human blood and the national standardization schemes in the United States, Japan, and Sweden: a method-comparison study. Clin Chem 2004;50(1):166-174.
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<p><a href="https://medelix.ai/en/calculators/hba1c-mmol-mol-to-percent">HbA1c mmol/mol → % 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.