A1C Chart: Blood Sugar Levels Explained in Plain English
Somebody handed you a number, maybe a 6.1, maybe a 7.8, and said “that’s your A1C.” If you are not sure what that number actually translates to in terms of everyday blood sugar readings, you are far from alone. This chart and guide breaks it down in plain English.
What A1C Actually Measures
The National Institute of Diabetes and Digestive and Kidney Diseases explains that the A1C test measures the percentage of your hemoglobin, a protein in red blood cells, that has sugar attached to it. Since red blood cells live about 90 to 120 days, this gives a rolling average of your blood sugar over roughly the past three months, rather than a single moment in time.
This is different from a home glucose meter or continuous glucose monitor, which shows your blood sugar right now. A1C smooths out the day-to-day ups and downs into one number.
The Full A1C to Estimated Average Glucose (eAG) Chart
Doctors sometimes describe your A1C in terms of an “estimated average glucose,” or eAG, since that number feels more familiar if you are used to checking your blood sugar directly. The conversion comes from a formula developed in ADA-sponsored research: eAG (mg/dL) = (28.7 x A1C%) minus 46.7.
| A1C | eAG (mg/dL) | eAG (mmol/L) | Category |
|---|---|---|---|
| 5.0% | 97 mg/dL | 5.4 mmol/L | Normal |
| 5.5% | 111 mg/dL | 6.2 mmol/L | Normal |
| 6.0% | 125 mg/dL | 6.9 mmol/L | Prediabetes |
| 6.5% | 140 mg/dL | 7.8 mmol/L | Diabetes |
| 7.0% | 154 mg/dL | 8.5 mmol/L | Diabetes |
| 7.5% | 169 mg/dL | 9.4 mmol/L | Diabetes |
| 8.0% | 183 mg/dL | 10.2 mmol/L | Diabetes |
| 8.5% | 197 mg/dL | 10.9 mmol/L | Diabetes |
| 9.0% | 212 mg/dL | 11.8 mmol/L | Diabetes |
| 9.5% | 226 mg/dL | 12.5 mmol/L | Diabetes |
| 10.0% | 240 mg/dL | 13.3 mmol/L | Diabetes |
| 10.5% | 255 mg/dL | 14.2 mmol/L | Diabetes |
| 11.0% | 269 mg/dL | 14.9 mmol/L | Diabetes |
| 11.5% | 283 mg/dL | 15.7 mmol/L | Diabetes |
| 12.0% | 298 mg/dL | 16.5 mmol/L | Diabetes |
| 12.5% | 312 mg/dL | 17.3 mmol/L | Diabetes |
| 13.0% | 326 mg/dL | 18.1 mmol/L | Diabetes |
| 13.5% | 341 mg/dL | 18.9 mmol/L | Diabetes |
| 14.0% | 355 mg/dL | 19.7 mmol/L | Diabetes |
These numbers are estimates based on population averages. Your own relationship between A1C and daily glucose readings can vary somewhat, which is one reason your healthcare provider looks at both A1C and, if you use one, your glucose meter or CGM data together.
What Counts as Normal, Prediabetes, and Diabetes
| A1C Range | Category | What It Means |
|---|---|---|
| Below 5.7% | Normal | Blood sugar is in a typical, healthy range |
| 5.7% to 6.4% | Prediabetes | Blood sugar is higher than normal, raising future risk |
| 6.5% or higher | Diabetes | Consistent with a diabetes diagnosis, typically confirmed with a second test |
According to Cleveland Clinic, a diabetes diagnosis is usually confirmed with a second test on a different day, unless symptoms and blood sugar levels are already very clearly elevated.
What Is a “Good” A1C Target?
There is no single number that applies to everyone. The American Diabetes Association generally recommends an A1C goal of below 7% for many adults with diabetes, but this is adjusted based on individual circumstances.
| Situation | Typical Approach |
|---|---|
| Otherwise healthy adult, newly diagnosed | A stricter goal, sometimes below 6.5%, may be appropriate |
| Older adults or those with other health conditions | A less strict goal, sometimes 7.5% to 8%, may be safer to avoid low blood sugar episodes |
| History of severe low blood sugar | A less aggressive target is often used for safety |
| Pregnancy | Different, tighter targets apply and are set by your provider |
What Can Throw Off an A1C Result
A1C is a reliable test for most people, but certain conditions can make it less accurate.
- Anemia or recent blood loss: Can falsely lower or raise results since the test relies on red blood cells
- Certain hemoglobin variants: Some genetic hemoglobin differences, more common in people of African, Mediterranean, or Southeast Asian descent, can interfere with standard A1C tests
- Kidney disease: Can affect red blood cell lifespan and skew results
- Pregnancy: Changes in blood volume and red blood cell turnover affect A1C accuracy
If your A1C result does not match what your glucose meter or CGM has been showing, mention it to your healthcare provider. They may use a different test, such as fructosamine, in certain situations.
How Often Should You Get Tested?
| Situation | Common Testing Frequency |
|---|---|
| Meeting treatment goals, stable | Twice a year |
| Not meeting goals, or treatment recently changed | Every 3 months |
| No diabetes, but risk factors present | As recommended by your provider, often every 1 to 3 years |
A1C vs. Daily Glucose Readings: What Is the Difference?
Think of A1C as the three-month average and daily glucose readings as individual data points. Both are useful, and they answer different questions.
- A1C tells you the big-picture trend over months, useful for tracking long-term progress
- Daily readings (finger stick or CGM) show what is happening right now, useful for understanding how specific meals, activities, or times of day affect you
Two people can have the same A1C with very different daily patterns, one with steady numbers all day, another with big swings that average out to the same number. That is part of why some healthcare providers also look at “time in range” data from a CGM alongside A1C.
How to Read Your Own Trend Over Time
A single A1C number matters less than the direction it is moving. A result of 7.2% might be discouraging on its own, but if your last test was 8.9%, that is meaningful progress. Keep a simple record of your results over time so you and your provider can see the trend, not just the latest snapshot.
Questions to Ask Your Healthcare Provider
- What is my personal A1C target, and why?
- How does my A1C compare to my last result?
- Is anything affecting the accuracy of my test, like anemia or kidney function?
- How often should I be retested?
- Should I also be tracking daily glucose readings, and if so, how often?
What to Do This Week
- Write down your most recent A1C result and the date of the test
- Use the chart above to see what estimated average glucose that number corresponds to
- If you have had more than one A1C test, compare the two to see the trend
- Prepare a short list of questions for your next appointment using the list above
The Bottom Line
A1C is a three-month average, not a daily snapshot, and the number that matters most is your own trend over time compared with a target set by your healthcare provider. Use the chart above as a reference, not a diagnosis.
Want a simpler way to understand type 2 diabetes or prediabetes? Join Type 2 Made Simple and get the free Type 2 Clarity Kit, a plain-English starter kit to help you understand your numbers, make easier food choices, and feel more prepared for doctor visits.
Frequently Asked Questions
What is a normal A1C level?
A normal A1C is below 5.7%. Between 5.7% and 6.4% is considered prediabetes, and 6.5% or higher is consistent with diabetes.
How do I convert my A1C to a blood sugar number?
Use the formula eAG (mg/dL) = (28.7 x A1C%) minus 46.7, or check the chart above for common values already calculated.
Can my A1C be wrong?
Yes, in certain situations. Anemia, some hemoglobin variants, kidney disease, and pregnancy can all affect A1C accuracy. Mention any of these to your healthcare provider.
How often should I get my A1C checked?
Many people who are meeting their goals get tested twice a year, while those adjusting treatment may be tested more often, around every 3 months. Ask your provider what is right for you.
Is a lower A1C always better?
Not necessarily for everyone. Very low targets can raise the risk of dangerously low blood sugar in some people, especially older adults. Your personal target should reflect your overall health picture.
This article is for general education only and is not medical advice. Always talk with your healthcare provider or a registered dietitian before making major changes to your diet, medication, or diabetes care plan.
