Convert between A1C and estimated average glucose (eAG).
Educational estimate, not medical advice.
How do you convert A1C to average blood glucose?
Estimated average glucose (eAG) in mg/dL = 28.7 × A1C − 46.7, using the ADAG study formula. For example, an A1C of 7% gives an eAG of about 154 mg/dL (8.6 mmol/L). An A1C below 5.7% is normal, 5.7–6.4% is prediabetes, and 6.5% or higher indicates diabetes.
Understanding your result
A1C reflects your average blood glucose over roughly three months, because glucose attaches to haemoglobin in red blood cells. The eAG translates that into the same units as a home meter. As a guide, below 5.7% is normal, 5.7–6.4% is prediabetes and 6.5% or higher is in the diabetes range. This is an estimate — always discuss results with a clinician.
Formula and method
eAG (mg/dL) = 28.7 × A1C − 46.7 (the ADAG study formula). Reverse: A1C = (eAG + 46.7) ÷ 28.7. To get mmol/L, divide mg/dL by 18.
Assumptions and limitations
This converts between A1C and estimated average glucose using a population formula, so it is an estimate for general information, not a diagnosis or a substitute for lab testing. Individual results can differ from the average because factors such as certain anaemias and red-cell conditions affect A1C. Always discuss your figures with a clinician.
Worked example
An A1C of 7% gives an estimated average glucose of 28.7 × 7 − 46.7 = 154 mg/dL (about 8.6 mmol/L).
How to use this tool
- Choose whether you know your A1C or your average glucose.
- Enter the value.
- Read the converted value and the category.
Common mistakes to avoid
- Treating eAG as a single reading rather than an average.
- Mixing mg/dL and mmol/L when comparing values.
- Using this estimate to change treatment without medical advice.
About the A1C Calculator
The A1C Calculator converts between A1C and estimated average glucose (eAG). Enter your A1C to see your average blood sugar in mg/dL and mmol/L, or enter a glucose level to estimate the matching A1C.
Who should use this tool
People managing diabetes or prediabetes, carers and health-curious users.
Benefits
- A1C to average glucose, and the reverse.
- Results in both mg/dL and mmol/L.
- Shows the normal, prediabetes and diabetes ranges.
- Private — calculated entirely in your browser.
Practical use cases
- Understanding what an A1C result means day to day.
- Comparing a meter average with an A1C.
- Tracking progress between lab tests.
Explore all Health and Nutrition tools
Frequently asked questions
What A1C is normal?
Below 5.7% is generally considered normal, 5.7–6.4% is prediabetes and 6.5% or above is in the diabetes range. Your clinician sets personal targets.
How does A1C relate to average glucose?
The eAG formula estimates average glucose as 28.7 × A1C − 46.7 mg/dL, so a 7% A1C is about 154 mg/dL.
Is this a substitute for a lab test?
No. It is an educational estimate. A laboratory A1C and your clinician's guidance remain the basis for any decisions.