HbA1c & Blood Glucose Converter

Convert HbA1c to estimated average glucose (ADAG equation), HbA1c percent to mmol/mol, and blood glucose between mg/dL and mmol/L.

Educational use only. Tool outputs have important limitations and cannot replace an individual assessment by an appropriately qualified healthcare professional.

Formulas used

Estimated average glucose (ADAG): eAG (mg/dL) = 28.7 × HbA1c (%) − 46.7. HbA1c (mmol/mol) = (HbA1c % − 2.15) × 10.929. Glucose (mmol/L) = glucose (mg/dL) ÷ 18.016.

HbA1c reference ranges (non-pregnant adults)

HbA1c	American Diabetes Association category
Below 5.7% (below 39 mmol/mol)	Below the prediabetes range
5.7% to 6.4% (39–47 mmol/mol)	Prediabetes range
6.5% or higher (48 mmol/mol or higher)	Diabetes range (diagnosis needs confirmation by a clinician)

Frequently asked questions

What is estimated average glucose (eAG)?

Estimated average glucose converts an HbA1c result into the average blood glucose level it corresponds to, in the same units as a glucose meter. It uses the equation from the A1C-Derived Average Glucose (ADAG) study: eAG (mg/dL) = 28.7 × HbA1c (%) − 46.7.

How do I convert HbA1c from percent to mmol/mol?

Laboratories report HbA1c either as a percentage (NGSP/DCCT units, common in the United States) or in mmol/mol (IFCC units, used in the United Kingdom, Europe and elsewhere). The conversion is mmol/mol = (percent − 2.15) × 10.929. For example, 7.0% is about 53 mmol/mol.

How do I convert blood glucose between mg/dL and mmol/L?

Divide mg/dL by 18.016 to get mmol/L, or multiply mmol/L by 18.016 to get mg/dL. For example, 100 mg/dL is about 5.6 mmol/L.

Why might my meter readings not match my estimated average glucose?

HbA1c reflects roughly the previous two to three months, while meter readings are single moments. Anaemia, recent blood loss or transfusion, some haemoglobin variants, kidney disease and pregnancy can make HbA1c less reliable. Discuss any mismatch with your clinician.

Can this calculator diagnose diabetes?

No. It converts units and estimates averages from published equations. Diagnosis and treatment decisions need laboratory testing and a clinician who knows your history.