A1C Conversion Chart: Turn Your A1C Into Average Glucose

This A1C conversion chart turns your A1C percentage into an estimated average glucose (eAG) value in the same units your glucose meter uses, mg/dL and mmol/L. If your lab report shows an A1C but you think in daily blood sugar numbers, the chart, the formula, and the worked examples below let you move between the two in seconds. In this article you will find the full A1C-to-eAG table, the exact formula, examples that answer common questions, and why your A1C can still differ from your meter or sensor average.

A1C to eAG conversion chart

Estimated average glucose (eAG) expresses your A1C as an average blood sugar level. The values below come from the standard formula used by the American Diabetes Association and are the same figures major medical centers publish.

The formula behind the conversion

If your exact A1C is not in the chart, the formula gives you any value. Estimated average glucose in mg/dL equals 28.7 multiplied by your A1C, minus 46.7:

eAG (mg/dL) = 28.7 × A1C − 46.7

To go the other way, from an average glucose back to an A1C, rearrange it: A1C (%) = (eAG + 46.7) ÷ 28.7. To switch between units, divide mg/dL by 18 to get mmol/L. These are the same calculations an online A1C calculator runs, so you can check any number yourself.

Worked examples

These examples answer the questions people ask most often:

• An A1C of 5.8% works out to about 120 mg/dL (6.7 mmol/L).
• An average blood sugar of 100 mg/dL corresponds to an A1C of about 5.1%.
• An average blood sugar of 120 mg/dL corresponds to an A1C of about 5.8%.
• An average blood sugar of 140 mg/dL corresponds to an A1C of about 6.5%, the threshold used to diagnose diabetes.
• An A1C of 7%, a common target for many adults with diabetes, equals an eAG of 154 mg/dL (8.6 mmol/L).

What eAG means, and what it does not

Estimated average glucose is a long-term average across roughly two to three months, not a snapshot. That is why your eAG will rarely match any single reading on your meter: a fasting number in the morning or a spike after a meal reflects one moment, while eAG blends thousands of moments together. Think of eAG as the season average and a fingerstick as a single at-bat. Both are useful, and they answer different questions. For a fuller explanation of what the underlying test measures, see our complete guide to hemoglobina glucosilada.

A quick reference for A1C ranges

The conversion is most useful when you also know where your A1C sits. These diagnostic bands apply to most non-pregnant adults, but individual targets vary, so confirm yours with your clinician.

For the full picture of targets, retesting, and what can raise or lower the number, read the HbA1c guide, or compare it with a same-day glucosa en ayuno.

Why your A1C and your meter or sensor average can disagree

The eAG from your A1C is an estimate, and it will not always line up with the average your continuous glucose monitor (CGM) reports. The CGM figure has its own name, the glucose management indicator (GMI), and recent research shows the two often differ.

A real-world study of people using CGM found that only about 1 in 10 had a close match between their lab A1C and their sensor-based estimate; half differed by half a percentage point or more. In everyday terms, your A1C could read 7.0% while your sensor suggests something meaningfully higher or lower. A follow-up study showed this gap is even wider in people with chronic kidney disease, where red-blood-cell turnover is altered. A 2025 review pulled these threads together into a practical checklist of what causes the mismatch, from sensor calibration to conditions that change red-blood-cell lifespan. What this means for you is simple: if your A1C and your daily numbers seem to tell different stories, that is common and worth discussing with your clinician rather than assuming one device is wrong. These are research findings that continue to be refined, but the takeaway is consistent.

Certain conditions also make the A1C itself less reliable, including anemia, recent blood loss or transfusion, pregnancy, and inherited hemoglobin variants that are more common in people of African, Mediterranean, or Southeast Asian descent. In those situations a clinician may rely more on direct glucose measures or a short-term marker such as Fructosamina.

Glosario

• A1C: a blood test reporting the percentage of hemoglobin coated with glucose, reflecting roughly 2 to 3 months of blood sugar.
• Estimated average glucose (eAG): your A1C expressed as an average blood sugar in mg/dL or mmol/L.
• Glucose management indicator (GMI): the average glucose estimated from continuous glucose monitor data.
• mg/dL: milligrams per deciliter, the glucose unit used in the United States.
• mmol/L: millimoles per liter, the glucose unit used in much of the world.
• mmol/mol: the unit some labs use to report A1C itself, alongside the percentage.
• Hemoglobin variant: an inherited form of hemoglobin that can make A1C results less accurate.

Preguntas frecuentes

What is my A1C if my average blood sugar is 140 mg/dL? About 6.5%, using the formula A1C = (140 + 46.7) ÷ 28.7. That value also happens to be the cutoff used to diagnose diabetes.

What average glucose does an A1C of 6.5% mean? Roughly 140 mg/dL (7.8 mmol/L), which marks the border between prediabetes and diabetes.

Is eAG the same as the average on my meter? Not exactly. eAG is a long-term estimate from your A1C, while your meter or CGM average covers a shorter, more recent window, so the two can differ.

How do I convert A1C to mmol/mol? That is a different conversion from eAG. Some labs report A1C in mmol/mol; as a rough guide, 6.5% is about 48 mmol/mol and 7% is about 53 mmol/mol.

Can I trust an online A1C calculator? Yes, if it uses the standard formula shown above. The chart on this page gives the same results, so you can cross-check any tool.

Why does my A1C seem high when my daily readings look fine? Overnight and post-meal glucose you do not measure can raise the average, and some conditions distort A1C. If the gap is large, ask your clinician to review both together.

Lecturas recomendadas

• Glycated hemoglobin (HbA1c): the complete guide
• Fasting blood glucose explained
• Blood glucose levels: causes and meaning
• Fructosamine: a shorter-term sugar marker
• Diabetes: causes, symptoms, and treatment

Fuentes

• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK, NIH). The A1C Test & Diabetes. https://www.niddk.nih.gov/health-information/diagnostic-tests/a1c-test
• American Diabetes Association. Understanding A1C and the eAG conversion. https://diabetes.org/about-diabetes/a1c
• Mayo Clinic. A1C test. https://www.mayoclinic.org/tests-procedures/a1c-test/about/pac-20384643
• Perlman JE, et al. HbA1c and Glucose Management Indicator Discordance: A Real-World Analysis. Diabetes Technol Ther, 2020. https://consensus.app/papers/details/09f59b200c6f5fc8985bea7730c1bdcf/
• Oriot P, et al. Discordance Between HbA1c and the Glucose Management Indicator in Diabetes and Chronic Kidney Disease. J Diabetes Sci Technol, 2022. https://consensus.app/papers/details/4edfb9f0f7d7585bbbd7ecd0ce5dd517/
• Lenters-Westra E, et al. Managing discordance between HbA1c and glucose management indicator. Diabetic Medicine, 2025. https://consensus.app/papers/details/cf3149da66a6524d8404938698139ed1/

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Converting your A1C is a first step; understanding it alongside your fasting glucose and other markers is the next. AI DiagMe reads your uploaded lab report and explains what your A1C, estimated average glucose, and related numbers may mean for you, in plain language, so you can prepare useful questions for your clinician. It helps you understand your results; it does not diagnose disease or replace your doctor.

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