A1C to Blood Sugar Converter
Convert your A1C percentage to estimated average blood sugar in both mg/dL and mmol/L using the ADAG formula.
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How to Convert A1C to Blood Sugar
The relationship between A1C and average blood sugar was established by the A1C-Derived Average Glucose (ADAG) study. This landmark study, published in Diabetes Care in 2008, monitored over 500 participants with continuous glucose monitors and frequent A1C tests to derive a reliable formula.
The formula converts A1C percentage directly to estimated average glucose (eAG), giving you a number that corresponds to the glucose values you see on your home meter or continuous glucose monitor. This makes it easier to understand what your A1C result means in practical, everyday terms.
A1C to Blood Sugar Formula
Example 1: A1C of 6.0%
eAG = 28.7 × 6.0 − 46.7 = 172.2 − 46.7 = 125.5 mg/dL (7.0 mmol/L)
Category: Prediabetes
Example 2: A1C of 9.0%
eAG = 28.7 × 9.0 − 46.7 = 258.3 − 46.7 = 211.6 mg/dL (11.8 mmol/L)
Category: Diabetes — significantly above target
A1C to Blood Sugar Conversion Table
Reference table showing A1C values from 5% to 12% and their corresponding average blood sugar levels.
| A1C (%) | eAG (mg/dL) | eAG (mmol/L) | Category |
|---|---|---|---|
| 5.0% | 96.8 | 5.4 | Normal |
| 5.5% | 111.2 | 6.2 | Normal |
| 6.0% | 125.5 | 7.0 | Prediabetes |
| 6.5% | 139.8 | 7.8 | Diabetes |
| 7.0% | 154.2 | 8.6 | Diabetes |
| 7.5% | 168.6 | 9.4 | Diabetes |
| 8.0% | 182.9 | 10.2 | Diabetes |
| 8.5% | 197.3 | 11.0 | Diabetes |
| 9.0% | 211.6 | 11.8 | Diabetes |
| 9.5% | 226.0 | 12.6 | Diabetes |
| 10.0% | 240.3 | 13.3 | Diabetes |
| 10.5% | 254.7 | 14.1 | Diabetes |
| 11.0% | 269.0 | 14.9 | Diabetes |
| 11.5% | 283.4 | 15.7 | Diabetes |
| 12.0% | 297.7 | 16.5 | Diabetes |
What Your Results Mean
Your estimated average glucose (eAG) helps you understand your A1C in terms you may be more familiar with from daily glucose monitoring. However, remember that eAG is an estimate — individual variation exists, and factors such as red blood cell lifespan, anemia, and hemoglobin variants can affect A1C accuracy.
If your A1C is in the prediabetes or diabetes range, consult your healthcare provider. Early intervention through diet, exercise, and if needed, medication can significantly improve outcomes.
The A1C to blood sugar relationship is not perfectly linear for every individual. The ADAG study found that while the formula works well for most people, there can be differences of up to 15 mg/dL between the calculated eAG and actual average glucose measured by continuous glucose monitors (CGMs).
Factors that can affect the accuracy of your A1C to glucose conversion include iron deficiency anemia (which may falsely elevate A1C), hemoglobin variants such as sickle cell trait, chronic kidney disease, and pregnancy. If you suspect your A1C does not accurately reflect your blood sugar levels, discuss alternative monitoring options like fructosamine testing with your healthcare provider.
When to Talk to Your Doctor About A1C
Understanding your A1C results is important, but knowing when to seek medical guidance is equally critical. If your A1C is 5.7% or higher, you should schedule an appointment with your healthcare provider to discuss your blood sugar levels and potential next steps, even if you feel fine.
Pay attention to trends over time. If your A1C has increased significantly since your last test — for example, rising by 0.5% or more — this warrants a conversation with your doctor, as it may indicate worsening blood sugar control or the need to adjust your treatment plan.
Be alert for common diabetes symptoms, including increased thirst, frequent urination, unexplained fatigue, blurred vision, and slow-healing wounds. These symptoms can develop gradually and may go unnoticed without regular screening.
The American Diabetes Association (ADA) recommends A1C testing every 3 to 6 months for people with diabetes, and at least twice a year for those meeting treatment goals. Regular monitoring helps you and your doctor catch changes early and take action before complications develop.
Frequently Asked Questions
What is the formula to convert A1C to blood sugar?
The ADAG formula converts A1C to estimated average glucose (eAG): eAG (mg/dL) = 28.7 × A1C − 46.7. For example, an A1C of 7% equals an eAG of about 154 mg/dL. For mmol/L: eAG = 1.5944 × A1C − 2.5944.
Is A1C the same as average blood sugar?
A1C reflects your average blood sugar over 2-3 months but is expressed as a percentage, not a glucose number. The eAG conversion translates that percentage into an average glucose value that is easier to relate to daily blood sugar readings.
What blood sugar level equals an A1C of 7%?
An A1C of 7% corresponds to an estimated average glucose of approximately 154 mg/dL (8.6 mmol/L). This is the target recommended by the ADA for most adults with diabetes.
Why does my meter reading differ from my eAG?
Your glucose meter measures blood sugar at a single point in time, while eAG is a weighted average over 2-3 months. Daily readings can vary widely due to meals, exercise, stress, and other factors, so a single reading may not match your average.