A1C Calculator
Type an A1C to see your estimated average blood glucose, or type an average glucose to get the A1C. Uses the ADAG formula endorsed by the American Diabetes Association.
For context only, not a diagnosis. A1C reflects your average over about 3 months.
How A1C converts to average glucose
eAG (mg/dL) = 28.7 x A1C - 46.7
eAG (mmol/L) = 1.59 x A1C - 2.59
These come from the ADAG study and are endorsed by the American Diabetes Association. For context: below 5.7% is normal, 5.7 to 6.4% is prediabetes, and 6.5% or higher is the diabetes range. Only a doctor can diagnose.
Source: Nathan DM et al., ADAG study group (2008); ADA.
Frequently asked questions
What does A1C measure?
A1C reflects your average blood sugar over roughly the past 3 months, by measuring the percentage of hemoglobin coated with glucose. It is a longer-term view than a single meter reading.
Why is my A1C different from my meter?
Your meter shows a single moment; A1C is a 3-month average. Both can be right at once. The eAG here translates A1C into the meter units you are used to.
What A1C is normal, prediabetes or diabetes?
For context only: below 5.7 percent is normal, 5.7 to 6.4 percent is the prediabetes range, and 6.5 percent or higher is the diabetes range. Only a doctor diagnoses.
Can A1C be inaccurate?
Yes. Anemia, certain hemoglobin variants, recent blood loss and pregnancy can skew it. Discuss any surprising result with your doctor.
Medical disclaimer: This calculator is for general information and education only. It is an estimate, not medical advice, diagnosis or treatment. Always talk to your doctor or midwife about your health and any decisions.