Estimate your A1C from an average glucose reading — or turn an A1C into the estimated average glucose (eAG) you actually see day-to-day. Works in mg/dL and mmol/L.
A1C (HbA1c) is a blood test reflecting your average blood sugar over the past ~2–3 months. Estimated average glucose (eAG) translates that percentage into the same mg/dL or mmol/L units your meter or CGM shows — so a lab result becomes something you can picture day-to-day.
This tool uses the ADAG study equation (Nathan et al., 2008), the same formula behind the American Diabetes Association's eAG conversion:
Common values, rounded. Find your A1C to see the matching estimated average glucose.
| A1C (%) | eAG (mg/dL) | eAG (mmol/L) |
|---|
Row highlighted in iris = the standard 7% target most adults with diabetes aim for (always confirm your personal goal with your clinician).
If your average comes from a continuous glucose monitor (CGM) over 14+ days, the Glucose Management Indicator (GMI) is the better estimate. It uses a different equation (Bergenstal et al., 2018) and can differ from your lab A1C by 0.3% or more.
GMI (%) = 3.31 + 0.02392 × mean glucose (mg/dL)
Use the ADAG formula: A1C (%) = (average glucose in mg/dL + 46.7) ÷ 28.7. For example, an average of 154 mg/dL works out to roughly a 7.0% A1C. In mmol/L, divide by 18 first to get mg/dL.
eAG expresses your A1C in the same units as your meter or CGM (mg/dL or mmol/L). It's not a separate test — it's a translation of your A1C so the number feels concrete instead of abstract.
No. This is a statistical estimate based on average glucose. A lab measures glycated hemoglobin directly. Individual factors — anemia, pregnancy, kidney disease, red-blood-cell lifespan, certain hemoglobin variants — can make your real A1C run higher or lower than the estimate.
GMI is calculated from your CGM's mean glucose over at least 14 days; A1C is a blood test. They often disagree by a few tenths of a percent because they measure glucose exposure differently. If you wear a CGM, GMI usually reflects your recent control more responsively.
About 154 mg/dL, or 8.6 mmol/L. A 6% A1C is roughly 126 mg/dL (7.0 mmol/L), and 8% is about 183 mg/dL (10.2 mmol/L).
Estimated A1C falls when your average glucose falls — which usually means increasing your time in range. Logging readings, spotting patterns (e.g. post-meal spikes), and reviewing them with your care team is the practical path. Tracking it daily is exactly what SteadyRange is built for. Never change medication on your own.
SteadyRange logs your glucose and weight, shows your time in range and estimated A1C as they move, and exports a clean PDF for your next appointment. Private by default.
Try SteadyRange →Medical disclaimer. This calculator is for general education only and uses population-average formulas (ADAG for eAG; Bergenstal et al. for GMI). It is an estimate, not a diagnosis, and is not a substitute for a laboratory A1C test or professional medical advice. Do not start, stop, or change any medication based on these numbers. Always consult a qualified healthcare provider about your results and goals.