Reading guide
How to use the A1C chart
Find the percentage from your laboratory A1C report in the first column. Read across that row to see estimated average glucose in mg/dL, the unit most often used by glucose meters and laboratories in the United States, or mmol/L, the glucose unit used in many other countries. The table moves in 0.1 percentage-point steps so it can preserve the precision commonly shown on a lab report.
Suppose your report shows 6.8%. The corresponding estimate is about 148 mg/dL, or 8.2 mmol/L. This does not mean your glucose stayed at 148 all day. Real readings rise after food, fall with activity or medication, and vary overnight. It means the A1C-to-eAG equation produces 148 mg/dL as a familiar summary of longer-term glucose exposure.
The last column provides broad screening categories for orientation. Below 5.7%, 5.7%–6.4%, and 6.5% or higher are commonly used laboratory thresholds for people who are not already known to have diabetes. Those labels are not personal treatment targets. For a focused explanation of screening ranges and confirmation, use our A1C levels chart.
How A1C becomes estimated average glucose
The table uses the A1C-Derived Average Glucose, or ADAG, relationship. Researchers compared laboratory A1C with extensive glucose monitoring and developed an equation that expresses A1C in the familiar units used for glucose. For US units, multiply A1C by 28.7 and subtract 46.7. To express that glucose estimate in mmol/L, divide the mg/dL result by approximately 18.018.
eAG (mg/dL) = 28.7 × A1C − 46.7
eAG (mmol/L) = eAG mg/dL ÷ 18.018
Displayed numbers are rounded for readability. A difference of one unit can occur if another chart rounds during an intermediate step. That small mathematical difference is not clinically meaningful and should not be mistaken for a change in glucose control.
A1C, eAG, and a device average are related—not interchangeable
A1C measures glycated hemoglobin in a blood sample. Because red blood cells circulate for weeks, the result reflects longer-term exposure rather than a single moment. Recent weeks may influence the result more than earlier weeks, so it should not be described as a simple arithmetic average of exactly 90 days.
eAG is calculated from A1C. It gives context in glucose units, but it is not independently measured. A meter average comes from the finger-stick readings stored by the device. Its usefulness depends on when and how often checks were made. A person who tests mainly before breakfast can have a device average that misses after-meal peaks. A CGM average includes far more readings, but gaps, compression lows, sensor problems, and short wear periods can still affect the summary.
GMI is another estimate found on many CGM reports. It uses mean CGM glucose and a different published equation to produce a percentage-like indicator. GMI should not be silently relabeled as laboratory A1C. When reviewing a report, write down whether each number is measured A1C, calculated eAG, device mean glucose, or GMI. Our GMI calculator explains that distinction in detail.
Why your readings may not match this chart
A noticeable difference does not automatically mean the laboratory or device is wrong. Glucose may have changed rapidly in the weeks before testing. Home data may cover only certain hours. Biological differences in how long red blood cells circulate can also shift the relationship between A1C and average glucose.
Anemia, iron status, kidney disease, pregnancy, recent bleeding, transfusion, treatment that changes red-cell production, and some hemoglobin variants may affect A1C or its interpretation. Some variants interfere with particular laboratory methods. If A1C repeatedly conflicts with well-collected meter or CGM data, ask a clinician to review the testing method, health history, and both data sources. Do not adjust medicine from this table alone.
What this conversion table cannot tell you
No daily pattern
A single eAG cannot reveal morning highs, after-meal spikes, overnight lows, or glucose variability.
No personal target
A target depends on diagnosis, pregnancy, age, medications, hypoglycemia risk, other conditions, and shared clinical decisions.
No test confirmation
A calculated row does not confirm or rule out diabetes. Laboratory testing and appropriate follow-up are required.
No medication decision
The chart does not include symptoms, glucose trends, dose timing, meals, kidney function, or other information needed for treatment.
Using the chart at a US medical appointment
Bring the original laboratory report rather than only a screenshot of a converted number. Record the test date, A1C percentage, any IFCC mmol/mol value, and the date range covered by your meter or CGM summary. If your glucose changed after a medication adjustment, illness, steroid treatment, travel, or a major routine change, mention the timing. It helps explain why current readings may differ from an A1C-based estimate.
Ask which metric should guide a specific decision. A clinician may use A1C to discuss longer-term progress, a glucose log to evaluate meals or medication timing, and CGM Time in Range to identify patterns that an average conceals. The metrics work best together when each is labeled accurately.
A1C chart questions
What blood sugar does a 7.0% A1C represent?
The ADAG equation gives an estimated average glucose of about 154 mg/dL, or 8.6 mmol/L. It is a population-based estimate rather than a measured fasting or after-meal reading.
Is this A1C chart the same as a blood sugar target chart?
No. This chart translates A1C into estimated average glucose. A target chart lists desired glucose ranges at particular times, such as before or after meals. Individual targets require clinical guidance.
Can an A1C chart diagnose diabetes?
A chart can show standard screening thresholds, but it cannot diagnose anyone. In the absence of unequivocal symptoms and very high glucose, an abnormal result is generally confirmed with repeat or another accepted laboratory test.
Why is my meter average different from the chart?
Finger-stick timing, missed readings, CGM coverage, recent glucose changes, red-blood-cell lifespan, anemia, kidney disease, pregnancy, hemoglobin variants, blood loss, or transfusion can contribute to a mismatch.
Does A1C show fasting blood sugar?
No. A1C reflects longer-term glucose exposure. It does not identify fasting glucose, after-meal spikes, overnight lows, or day-to-day variability.
How do I convert eAG from mg/dL to mmol/L?
For glucose, divide mg/dL by approximately 18.018. Do not use that operation to convert A1C percentage into IFCC mmol/mol; HbA1c uses a different equation.
Sources and editorial note
The conversion equation comes from the ADAG study in Diabetes Care. Test meaning and limitations are informed by the National Institute of Diabetes and Digestive and Kidney Diseases and CDC A1C guidance. Reviewed August 15, 2026. This page is educational and does not replace diagnosis or individual medical advice.