A1C → glucose — Quick answer
A1C reflects average glucose over ~2–3 months; eAG converts it to a glucose figure.
eAG (mg/dL) = 28.7 × A1C − 46.7 · eAG (mmol/L) = 1.59 × A1C − 2.59
Worked example: A1C 7% → 28.7×7 − 46.7 = 154 mg/dL (8.5 mmol/L).
A1C reference
| A1C | eAG | Band |
|---|
| 5.0% | 97 mg/dL | Normal |
| 5.7% | 117 mg/dL | Prediabetes |
| 6.5% | 140 mg/dL | Diabetes range |
| 7.0% | 154 mg/dL | Diabetes range |
Educational only — diagnosis and treatment come from a clinician with your lab results.
Standards & method
✓ Independently verified 12 July 2026- Governing standard
- ADA / NGSP — Nathan et al., Diabetes Care 2008 (A1c-Derived Average Glucose study)
- Clauses applied
- The ADAG regression relating HbA1c to estimated average glucose, adopted by the American Diabetes Association.
- Core formula
eAG (mg/dL) = 28.7 × A1c(%) − 46.7 · eAG (mmol/L) = 1.59 × A1c − 2.59- Why this matters
- eAG is an average — it says nothing about glycaemic variability, and two people with the same A1c can have very different hypoglycaemia risk. A1c is also unreliable in anaemia, haemoglobinopathies and pregnancy. This is general information, not medical advice — discuss any health decision with a qualified clinician.
- Independently verified
- 12 July 2026 — Re-derived from the governing standard and checked numerically against worked reference cases from the standard itself — not merely tested for “returns a number”.
Results are for guidance. Verify against the current edition of the governing standard and have a qualified professional review before use in practice.
A1C (HbA1c) is a percentage that reflects your average blood glucose over about 2–3 months. This tool converts it to estimated average glucose (eAG) using the ADAG formula — eAG mg/dL = 28.7 × A1C − 46.7 — and back again, and shows where the A1C falls among the normal, prediabetes and diabetes bands.
Reviewed: June 20, 2026 · Author: Naveen P N, Founder — AI Calculator · Verified against: the ADAG eAG equations, recomputed in code. Educational only, not medical advice.
The conversion formulas
These come from the international ADAG study, which related lab A1C to continuously-measured average glucose. The mg/dL and mmol/L lines are the same relationship in the two glucose units. Standard A1C bands are below 5.7% normal, 5.7–6.4% prediabetes, and 6.5% or higher in the diabetes range.
Worked examples
A1C of 7%:
A1C of 5.7% (prediabetes threshold):
Average glucose of 154 mg/dL back to A1C:
So an A1C of 7% corresponds to an average glucose around 154 mg/dL, and 6.5% — the diabetes threshold — to about 140 mg/dL. Remember eAG is a long-run average, not a snapshot from a meter.
Frequently Asked Questions
How do I convert A1C to average glucose?⌄
eAG mg/dL = 28.7 × A1C − 46.7; mmol/L = 1.59 × A1C − 2.59. A1C 7% ≈ 154 mg/dL (8.5 mmol/L).
What A1C means diabetes?⌄
Bands: <5.7% normal, 5.7–6.4% prediabetes, ≥6.5% diabetes range. A clinician makes the diagnosis.
Is eAG my meter reading?⌄
No. eAG is a 2–3 month average from A1C; a glucometer is one moment that swings with meals and time.
Convert glucose back to A1C?⌄
A1C = (mg/dL + 46.7) / 28.7. 154 mg/dL ≈ 7%. An estimate, not a lab test.
What period does A1C cover?⌄
About the prior 2–3 months, since red cells live that long. It smooths out daily swings.