eAG to A1c Calculator
Convert between estimated average glucose (eAG) and A1c in either direction — enter an eAG to get the A1c, or an A1c to get the eAG, in mg/dL and mmol/L.
How to Use This Calculator
- Choose the direction — A1c → eAG, or eAG → A1c.
- Enter the value you have (an A1c in %, or an average glucose in mg/dL).
- Read the converted result in both mg/dL and mmol/L.
eAG is the average glucose statistically linked to an A1c — not a measured reading — so your real meter or CGM average may differ.
The eAG ↔ A1c Formula
Estimated average glucose expresses an A1c in the same units as a glucose meter, which many people find easier to relate to. The conversion uses the ADAG study regression:
Example: A1c 7.0% → 28.7 × 7 − 46.7 = 154 mg/dL (8.6 mmol/L).
A1c and eAG Reference Table
| A1c (%) | eAG (mg/dL) | eAG (mmol/L) |
|---|---|---|
| 6.0 | 126 | 7.0 |
| 6.5 | 140 | 7.8 |
| 7.0 | 154 | 8.6 |
| 8.0 | 183 | 10.2 |
| 9.0 | 212 | 11.8 |
For an A1c estimated from a CGM average, see GMI; for A1c from a meter average, see the HbA1c calculator.
What Your A1c Means: Diagnosis & Reliability
A1c diagnostic thresholds
A1c is used both to diagnose and to track diabetes. The standard cut-offs are under 5.7% (normal), 5.7–6.4% (prediabetes), and 6.5% or higher (diabetes), usually confirmed on a repeat test. For most adults with diabetes the management target is below about 7%, individualized by your care team.
When A1c can be misleading
Because A1c depends on red blood cells, anything that changes their lifespan or your hemoglobin can throw it off. It can read falsely high with iron-deficiency anemia or kidney failure, and falsely low after recent blood loss or transfusion, in hemolytic anemia, later pregnancy, or with sickle cell trait and other hemoglobin variants. In these situations, CGM metrics such as GMI and time in range often give a truer picture.
Frequently Asked Questions
What is eAG?
Estimated average glucose (eAG) translates an A1c percentage into an average glucose in mg/dL or mmol/L, the same units as a glucose meter. It makes A1c easier to relate to everyday readings.
How do you convert A1c to average glucose?
Use eAG = 28.7 × A1c − 46.7 for mg/dL, then divide by 18.016 for mmol/L. For example, an A1c of 7% gives an eAG of about 154 mg/dL (8.6 mmol/L).
Is eAG the same as my meter or CGM average?
Not exactly. eAG is derived from your A1c using a population formula, while your meter or CGM average is your actual measured data. They can differ, which is normal and clinically informative.
How is this different from GMI?
GMI starts from a measured CGM average glucose and estimates an A1c-like value. eAG starts from an A1c and estimates an average glucose. They use different equations and serve opposite directions.
What A1c level means I have diabetes?
An A1c of 6.5% or higher indicates diabetes, 5.7–6.4% indicates prediabetes, and under 5.7% is normal. A diagnosis is usually confirmed with a repeat test or a second measure such as fasting glucose, and made by a clinician.
Why might my A1c be inaccurate?
A1c relies on red blood cells, so conditions that change their lifespan or your hemoglobin can distort it. Iron-deficiency anemia and kidney failure can raise it, while recent blood loss or transfusion, hemolytic anemia, later pregnancy, and hemoglobin variants like sickle cell trait can lower it. CGM-based measures like GMI and time in range help when A1c is unreliable.
Sources
- Nathan DM, et al. Translating the A1C assay into estimated average glucose values (ADAG study). Diabetes Care. 2008.
- American Diabetes Association. eAG/A1c conversion and Standards of Care.
Last reviewed: June 2025