A1C Calculator
Convert HbA1c to estimated average glucose (eAG) and back, in mg/dL, mmol/L and mmol/mol.
About the A1C Calculator
HbA1c reflects average blood sugar over the past 2–3 months. The ADAG study (2008) established the linear relationship used by the American Diabetes Association to translate it into an estimated average glucose.
The formula
eAG (mg/dL) = 28.7 × HbA1c − 46.7
- mmol/L
- mg/dL ÷ 18.016
- IFCC (mmol/mol)
- (HbA1c% − 2.15) × 10.929
HbA1c and average glucose
| HbA1c | mg/dL | mmol/L |
|---|---|---|
| 5% | 97 | 5.4 |
| 5.7% | 117 | 6.5 |
| 6% | 125 | 7 |
| 6.5% | 140 | 7.8 |
| 7% | 154 | 8.6 |
| 8% | 183 | 10.2 |
| 9% | 212 | 11.7 |
| 10% | 240 | 13.3 |
| 11% | 269 | 14.9 |
| 12% | 298 | 16.5 |
Worked example
Example: Estimated average glucose = 160 mg/dL (8.9 mmol/L)
- Inputs: Convert: HbA1c → glucose; HbA1c: 7.2%.
- Formula: eAG (mg/dL) = 28.7 × HbA1c − 46.7
- Result: Estimated average glucose = 160 mg/dL (8.9 mmol/L)
- HbA1c (IFCC): 55 mmol/mol
- Category (ADA): Diabetes range (6.5% or above)
Things to keep in mind
- This is an estimate for general information, not medical advice. Talk to a doctor or other qualified professional about your health.
- Anaemia, some haemoglobin variants and pregnancy can make HbA1c less reliable.
Questions people ask
What HbA1c means diabetes?
6.5% or above on two tests; 5.7–6.4% is the prediabetes range (American Diabetes Association).
Why doesn't it match my meter?
eAG is an average over months; finger-stick readings capture single moments.