Estimated Average Glucose
Convert your HbA1c percentage to estimated average glucose (eAG) in mg/dL and mmol/L using the validated ADAG formula. Free diabetes calculator with normal ranges, charts, and detailed interpretation for blood sugar management.
About This Calculator
What is Estimated Average Glucose (eAG)?
The Estimated Average Glucose (eAG) Calculator converts your HbA1c (glycated hemoglobin) percentage into your estimated average blood sugar level over the past 3 months. This conversion helps translate HbA1c results — which many patients find confusing — into the same units (mg/dL or mmol/L) used for everyday blood glucose monitoring.
The calculator uses the formula validated by the international A1c-Derived Average Glucose (ADAG) Study published in Diabetes Care (2008): eAG (mg/dL) = 28.7 × HbA1c − 46.7. For example, an HbA1c of 7% translates to an estimated average glucose of approximately 154 mg/dL (8.6 mmol/L).
This tool is designed for people with diabetes, prediabetes, and healthcare professionals in India, the United States, the United Kingdom, and worldwide who need to interpret HbA1c results in terms of average blood glucose levels.
Regional Notes
- India: HbA1c targets recommended by the Research Society for the Study of Diabetes in India (RSSDI) are generally below 7% for most adults. Results are commonly reported in mg/dL and percentage (%).
- United States: The American Diabetes Association (ADA) recommends HbA1c below 7% for most non-pregnant adults. Results are reported as a percentage with eAG in mg/dL.
- United Kingdom: The National Institute for Health and Care Excellence (NICE) recommends HbA1c targets of 6.5-7% (48-53 mmol/mol). The UK uses IFCC units (mmol/mol) alongside DCCT percentage. eAG is often reported in mmol/L.
How the Formula Works
Red blood cells have a lifespan of approximately 120 days. During this time, glucose molecules bind to hemoglobin A — the higher the blood sugar level, the more glycation occurs. HbA1c measures the percentage of glycated hemoglobin, reflecting average blood glucose over the preceding 2-3 months. The ADAG formula provides a linear regression that converts this percentage into the equivalent average glucose concentration in the blood.
Frequently Asked Questions
What is estimated average glucose (eAG)?
Estimated average glucose (eAG) is a calculated value that converts your HbA1c percentage into an average blood sugar level in mg/dL or mmol/L over the past 3 months. It is derived from the ADAG (A1c-Derived Average Glucose) study formula: eAG (mg/dL) = 28.7 × HbA1c − 46.7.
How do I convert HbA1c to estimated average glucose?
To convert HbA1c to eAG, use the formula: eAG (mg/dL) = 28.7 × HbA1c − 46.7. For example, an HbA1c of 7% gives eAG = (28.7 × 7) − 46.7 = 154 mg/dL (8.6 mmol/L). Our calculator does this instantly.
What is a normal eAG level?
For non-diabetics, a normal HbA1c is below 5.7%, which corresponds to an eAG below 117 mg/dL (6.5 mmol/L). Prediabetes ranges from 5.7% to 6.4% (eAG 117-140 mg/dL), and diabetes is 6.5% or higher (eAG above 140 mg/dL).
How accurate is the eAG formula?
The formula eAG = 28.7 × HbA1c − 46.7 was validated by the international ADAG study published in Diabetes Care (2008), which analyzed over 2,700 glucose measurements from 507 participants across 10 international centers. It provides a reliable estimate of average glucose over the preceding 3 months.
What is the difference between eAG and eAG (mmol/L)?
eAG can be expressed in mg/dL (milligrams per deciliter), commonly used in India and the United States, or mmol/L (millimoles per liter), commonly used in the United Kingdom and many other countries. To convert mg/dL to mmol/L, divide by 18.015. Our calculator shows both units.
How often should I check my HbA1c?
The American Diabetes Association recommends testing HbA1c at least twice a year for people with stable blood sugar control, and quarterly for those whose therapy has changed or who are not meeting glycemic goals. Consult your healthcare provider for a personalized schedule.
Can I use eAG to adjust my diabetes medication?
While eAG provides a useful overview of your average blood sugar over 3 months, it should not be used alone to make medication adjustments. Always consult your healthcare provider for treatment decisions. Use eAG alongside daily self-monitoring and professional medical advice for comprehensive diabetes management.
What HbA1c target should I aim for?
In India and the US, the general HbA1c target for most adults with diabetes is below 7% (eAG below 154 mg/dL). In the UK, the target is typically below 7% (53 mmol/mol) or as agreed with your diabetes care team. Less stringent targets (below 8%) may be appropriate for older adults or those with comorbidities. Always follow your healthcare provider's individualized target.