Diabetes and metabolic
HbA1c to average glucose
HbA1c reflects average blood glucose over roughly the last three months. This converts the percentage into an average glucose, which is the number most patients can actually picture.
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The result appears as you type.
Nothing is sent anywhere. The calculation runs entirely in your browser.
This calculator is provided for reference and education. It does not replace clinical assessment, examination, current guidelines, local protocol, or professional judgment. Verify every result before acting on it. Nirogix accepts no liability for clinical decisions made using this tool.
The formula
- eAG (mg/dL) = 28.7 × HbA1c(%) − 46.7
- eAG (mmol/L) = eAG (mg/dL) ÷ 18.016
- IFCC (mmol/mol) = (HbA1c% − 2.15) × 10.929
Worked example
HbA1c 7.0% → 28.7 × 7 − 46.7 = 154 mg/dL
When to use it
- Explaining an HbA1c result to a patient
- Comparing an HbA1c against home glucose readings
And when not to
- HbA1c is unreliable in anemia, hemoglobinopathy, recent transfusion, pregnancy and chronic kidney disease, all of which are common in this population.
- It hides variability. A person with frequent hypoglycemia can have a reassuring HbA1c.
References
- Translating the A1C assay into estimated average glucose values — Nathan DM et al., Diabetes Care (ADAG study), 2008
Last reviewed 07/09/2026.
These calculators are free and always will be. We also build Nirogix, a hospital management system for Indian clinics and hospitals. The same calculations are planned inside the consultation record, pre-filled from the chart.