An A1C calculator converts your A1C percentage into estimated average glucose, the blood sugar number in mg/dL that the same A1C reflects. Formula: eAG (mg/dL) = 28.7 × A1C − 46.7; A1C = (eAG + 46.7) ÷ 28.7. Using the American Diabetes Association formula, an A1C of 7% equals an estimated average glucose of 154 mg/dL, and 6.5% equals 140 mg/dL.
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How to use the A1C calculator
- Choose the direction: A1C to estimated average glucose, or average glucose to A1C.
- Enter the A1C percent from your lab report, or an average glucose in mg/dL.
- Read the result.
The A1C calculator does a unit conversion only. It does not judge whether a number is good or bad for you.
What formula does the A1C calculator use?
The American Diabetes Association gives the relationship as 28.7 × A1C − 46.7 = eAG, where eAG is estimated average glucose in mg/dL. The formula comes from the A1C-Derived Average Glucose (ADAG) study, published in Diabetes Care in 2008 by Nathan and colleagues. To go the other way, the A1C calculator adds 46.7 to the glucose and divides by 28.7.
A1C calculator conversion table
Results from the A1C calculator, which match the ADA’s published table:
| A1C | Estimated average glucose |
|---|---|
| 6% | 126 mg/dL |
| 6.5% | 140 mg/dL |
| 7% | 154 mg/dL |
| 7.5% | 169 mg/dL |
| 8% | 183 mg/dL |
| 9% | 212 mg/dL |
| 10% | 240 mg/dL |
Each 1-point rise in A1C adds about 29 mg/dL to the estimated average.
What A1C measures
NIDDK explains that the A1C test reflects your average blood glucose over the past 3 months. Glucose attaches to hemoglobin in red blood cells, and the test reports the share of hemoglobin with glucose attached as a percentage. Because it is an average, it does not show highs and lows during the day. Two people with the same A1C can have very different daily patterns.
How A1C results are grouped
NIDDK lists these diagnostic ranges: below 5.7% is normal, 5.7% to 6.4% is prediabetes, and 6.5% or above is diabetes. It adds that a diagnosis needs a second test to confirm, unless there are clear symptoms. For most people living with diabetes, the ADA recommends an A1C target of 7% or less, but your own target may be higher or lower.
The A1C calculator cannot tell you which range fits you or what your target should be. Talk to your doctor about your results.
Results in mmol/L
Many countries report glucose in mmol/L rather than mg/dL. The ADA’s own conversion table lists both. For example, an A1C of 7% matches about 8.6 mmol/L, and 8% matches about 10.1 mmol/L. To convert any mg/dL number roughly, divide it by 18. Glucose meters and lab reports usually say which unit they use, so check before you compare numbers from different sources.
Questions to bring to your appointment
If you are tracking your numbers, it can help to write down a few questions before a visit. What A1C target is right for me, and why? How often should I be tested? Does my meter or sensor average match my lab result, and if not, what could explain the gap? Are any of my other health conditions likely to affect the test? Bringing your recent readings and the converted number from this page gives you and your doctor a shared starting point. Only your care team can tell you what the results mean for you.
When A1C and eAG may not match
Some conditions that affect red blood cells, such as certain types of anemia or recent blood loss, can make an A1C result less reliable, as MedlinePlus explains. Your meter or sensor average may also differ from the eAG, because it depends on when and how often you check. If your numbers do not line up, talk to your doctor. Do not change any medicine based on the A1C calculator.
For information only. This is not medical advice or a diagnosis; talk to your doctor about your results.
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Sources
American Diabetes Association: eAG/A1C conversion calculator; American Diabetes Association: Understanding A1C; NIDDK: The A1C test and diabetes; MedlinePlus: Hemoglobin A1C (HbA1c) test.
Questions about this calculator
What is 7 A1C in average glucose?
About 154 mg/dL, using the ADA formula 28.7 × 7 − 46.7.
How is eAG calculated from A1C?
eAG in mg/dL = 28.7 × A1C − 46.7, from the ADAG study.
What A1C is normal?
NIDDK lists below 5.7% as normal, 5.7% to 6.4% as prediabetes and 6.5% or above as diabetes. Talk to your doctor about your own result.
How long does A1C reflect?
About the past 3 months, according to NIDDK.
Can I use the A1C calculator to diagnose diabetes?
No. It converts numbers. A diagnosis needs lab testing and your doctor.
Check the assumptions and units before relying on a result. Financial, tax and health estimates do not replace advice for your individual circumstances.
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