A1c to average glucose converter
Enter your A1c percentage to see the estimated average glucose (eAG) it corresponds to, based on the ADAG study formula used in clinical practice.
How this is calculated
This tool uses the formula from the ADAG (A1c-Derived Average Glucose) study, published in Diabetes Care, which established the relationship between A1c and average blood glucose over the preceding 2–3 months:
eAG (mg/dL) = 28.7 × A1c − 46.7
This is an estimate, not a diagnosis. Individual factors — including red blood cell lifespan, certain anemias, and pregnancy — can shift the real relationship between A1c and glucose for a given person. Always interpret your A1c with a clinician who knows your history.
| A1c | eAG (mg/dL) | eAG (mmol/L) |
|---|
Frequently asked questions
What is a normal A1c level?
Below 5.7% is generally considered within the non-diabetic range. 5.7%–6.4% is classified as prediabetes, and 6.5% or above on two separate tests is generally used to diagnose diabetes. Your own target may differ based on age, other conditions, and how long you've had diabetes — this is something to set with your clinician, not from a general chart.
Is eAG the same as my glucose meter reading?
No. eAG is an estimated average across roughly 2–3 months, derived from your A1c. A single glucose meter or CGM reading reflects your blood sugar at one moment, which naturally moves up and down throughout the day. The two numbers measure different things and won't match exactly.
How often should A1c be checked?
For most people with well-controlled diabetes, every 6 months is typical. If treatment has recently changed, or control is not yet at target, every 3 months is more common. This tool doesn't replace that testing schedule — talk to your care team about what's right for you.
Why might my A1c and my average glucose readings not match this formula?
The ADAG formula is a population average. Conditions affecting red blood cells (such as certain anemias, kidney disease, or recent blood loss/transfusion) can make A1c read higher or lower than your true average glucose. If your device-measured average glucose consistently disagrees with what this calculator predicts from your A1c, mention it to your clinician.