A1C to eAG Calculator
Convert HbA1c to estimated average glucose (eAG) and back, using the ADAG study equation. Enter your A1C as a percentage, or enter an average glucose to see the matching A1C. Results are shown in both mg/dL and mmol/L.
A1C and estimated average glucose
| A1C (%) | eAG (mg/dL) | eAG (mmol/L) |
|---|
Frequently asked questions
How do you convert A1C to average glucose?
The ADAG study formula is eAG (mg/dL) = 28.7 × A1C − 46.7, where A1C is the percentage. In SI units, eAG (mmol/L) = 1.59 × A1C − 2.59. For example, an A1C of 7% gives an estimated average glucose of about 154 mg/dL (8.6 mmol/L).
What is eAG?
eAG stands for estimated average glucose. It re-expresses your HbA1c as an average blood-glucose number in the same units you see on a home meter (mg/dL or mmol/L), which many people find easier to relate to than a percentage. It is a statistical estimate of the average over the previous 2–3 months, not a single reading.
Is eAG the same as my meter or CGM average?
Not exactly — eAG is derived from your A1C, while a meter or CGM average is measured directly. They often differ, because A1C reflects red-blood-cell glucose exposure and can be affected by anaemia, recent blood loss, pregnancy, certain haemoglobin variants and red-cell lifespan. A gap between the two is common and worth discussing with your clinician.
What A1C corresponds to a normal average glucose?
As a rough guide: A1C 5% ≈ 97 mg/dL (5.4 mmol/L), 6% ≈ 126 mg/dL (7.0), 7% ≈ 154 mg/dL (8.6), 8% ≈ 183 mg/dL (10.2) and 9% ≈ 212 mg/dL (11.8). Diagnostic and target A1C values vary by guideline and by person — this tool converts numbers, it does not set targets. The reference table under the calculator runs the same equation across A1C values from 5% to 12%, so you can read off any point in that range. Every figure comes from the ADAG regression itself, not from a diagnostic threshold.
Can I convert average glucose back to A1C?
The A1C to eAG conversion runs in both directions. Rearranging the formula, A1C (%) = (eAG in mg/dL + 46.7) ÷ 28.7. Enter a glucose value in the eAG field above and the calculator fills in the matching A1C automatically. Remember this is the reverse of a population estimate, so it is an approximation.
This is a reference tool, not a diagnosis or medical advice. Results depend on the laboratory, assay and clinical context, and reference intervals vary between labs and by age and sex — always read your result against the range printed on your own report and discuss it with a qualified healthcare professional.
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