A1c to Blood Glucose Calculator
Convert HbA1c to estimated average glucose and back, in mg/dL and mmol/L. Educational, not medical advice.
Uses the ADAG formula: eAG (mg/dL) = 28.7 × A1c − 46.7. For example, an A1c of 7% works out to about 154 mg/dL (8.6 mmol/L). This is a population average — your day-to-day readings will swing above and below it, and individual red-blood-cell turnover can shift the relationship.
This is an educational estimate, not medical advice. Numbers here can't diagnose or rule out any condition. Talk to a qualified clinician about your own health.
How it works
HbA1c is a blood test that reflects your average blood sugar over the past two to three months. It's reported as a percentage, and higher percentages mean more sugar has been stuck to your red blood cells over that window. Estimated average glucose (eAG) translates that percentage into the same units your home meter uses.
The conversion comes from the ADAG study: eAG in mg/dL = 28.7 × A1c − 46.7. So an A1c of 7% maps to about 154 mg/dL, which is roughly 8.6 mmol/L. Flip the tool around and it runs the formula in reverse, turning an average glucose back into an approximate A1c.
This gives you a common yardstick — it's easier to picture 154 mg/dL than 7%. But eAG is an average across months, so your finger-stick readings will naturally run higher after meals and lower when fasting. The formula also assumes typical red-blood-cell lifespan, which some conditions change.
Frequently asked questions
What glucose does an A1c of 7% equal?
About 154 mg/dL, or roughly 8.6 mmol/L, using the ADAG formula eAG = 28.7 × A1c − 46.7. That figure is an estimated average over the previous two to three months, not a single moment-in-time reading.
Why doesn't my meter match the eAG?
Your meter captures one instant, while eAG is a long-run average. Readings swing up after eating and down when fasting, so any single measurement can sit well above or below the eAG. Both can be accurate at once — they're describing different things.
Is the A1c-to-glucose conversion always reliable?
It's a population-based estimate. Conditions that shorten or lengthen red-blood-cell lifespan — like certain anemias, recent transfusions, or pregnancy — can throw the relationship off. Use this as a rough translation and let your clinician interpret your actual lab results.