eAG Calculator · Estimated Average Glucose

Estimated Average Glucose (eAG) Calculator

Convert HbA1c to estimated average glucose (eAG) in mg/dL and mmol/L.

Do you suffer from diabetes?

No Yes

Enter HbA1c

HbA1c (%)

eAG (mg/dL)

mg/dL

eAG (mmol/L)

mmol/L

Quick examples

Formula: eAG (mg/dL) = 28.7 × A1C − 46.7 · eAG (mmol/L) = eAG (mg/dL) ÷ 18.0182
Based on the ADAG study (Nathan et al., 2008).

Results

✅ Optimal Control

HbA1c: 7.0%
Estimated Average Glucose: 154.2 mg/dL (8.6 mmol/L)

📊 HbA1c

7.0%

📈 eAG (mg/dL)

154.2

📉 eAG (mmol/L)

8.6

📊 Status

Optimal

💡 Interpretation

Your HbA1c of 7.0% corresponds to an estimated average glucose of 154 mg/dL (8.6 mmol/L). This is within the recommended target range for many people with diabetes.

📋 ADA Reference Ranges

Normal: < 5.7%

Pre-diabetes: 5.7–6.4%

Diabetes: ≥ 6.5%

Target: < 7.0%

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Creator & Maintainer

Faiq Ur Rahman is a web designer, digital product developer, and founder of Toolraxy, a growing platform of web-based calculators and utility tools. He specializes in building structured, user-friendly tools focused on health, finance, productivity, and everyday problem-solving.

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Introduction

The Estimated Average Glucose (eAG) Calculator bridges the gap between HbA1c laboratory results and day-to-day blood glucose monitoring. For people managing diabetes, understanding the relationship between their HbA1c percentage and their average blood glucose levels is essential for effective treatment planning and lifestyle adjustments.

This calculator uses the validated ADAG (A1c-Derived Average Glucose) formula established by Nathan et al. in 2008, which provides the most accurate conversion between HbA1c and average glucose. By entering your HbA1c percentage and selecting your diabetes status, you’ll receive your eAG in both mg/dL and mmol/L formats, along with an interpretation of your results and a status classification.

Healthcare providers frequently use this conversion during patient consultations, as it translates the three-month average measured by HbA1c into the same units patients see on their daily glucose meters. This makes the concept of glycemic control more tangible and actionable for patients.

How to Use the eAG Calculator

Select your diabetes status by choosing either “Yes” or “No” to indicate whether you have diabetes.
Enter your HbA1c percentage in the input field (typically between 3.0% and 20.0%).
Use the quick example buttons beneath the input field to test common HbA1c values instantly.
View your estimated average glucose (eAG) displayed in both mg/dL and mmol/L units.
Check your status classification shown as a colored badge (Normal, Pre-diabetes, Target Range, Elevated, High, Very High, or Diabetes Range).
Read the personalized interpretation explaining what your results mean for your health.
Review the ADA reference ranges displayed for quick comparison with standard guidelines.
Copy, share, or embed your results using the buttons below the calculator.

How the eAG Calculator Formula Works

The calculator converts HbA1c percentage to estimated average glucose using the validated ADAG study formula, which is the standard conversion equation endorsed by the American Diabetes Association (ADA).

Formula: eAG (mg/dL) = 28.7 × HbA1c − 46.7

Conversion to mmol/L: eAG (mmol/L) = eAG (mg/dL) ÷ 18.0182

For example, an HbA1c of 7.0% converts to:

eAG (mg/dL) = (28.7 × 7.0) − 46.7 = 200.9 − 46.7 = 154.2 mg/dL
eAG (mmol/L) = 154.2 ÷ 18.0182 = 8.6 mmol/L

The calculator automatically clamps any input below 3.0% or above 20.0% to ensure results remain within clinically meaningful ranges. The diabetes status selection determines which classification scheme applies different thresholds are used for individuals with and without diagnosed diabetes.

Worked Example

A 58-year-old man with Type 2 diabetes visits his endocrinologist for a routine check-up. His latest HbA1c result is 8.3%. He uses the calculator to understand what this means for his average daily glucose:

Input: HbA1c = 8.3%, Diabetes Status = Yes

Calculations:

eAG (mg/dL) = (28.7 × 8.3) − 46.7 = 238.21 − 46.7 = 191.5 mg/dL
eAG (mmol/L) = 191.5 ÷ 18.0182 = 10.6 mmol/L

Status Classification (Diabetic): High

Interpretation: His HbA1c of 8.3% corresponds to an estimated average glucose of 191.5 mg/dL (10.6 mmol/L). This is high (above 8.0%), indicating his glucose levels have been significantly elevated over the past three months. His healthcare provider recommends reviewing his medication regimen, increasing physical activity, and monitoring his carbohydrate intake to bring his HbA1c back toward the target of 7.0%.

Frequently Asked Questions

What is the eAG Calculator and how does it work?

The eAG Calculator is a tool that converts your HbA1c percentage to estimated average glucose (eAG) using the ADAG formula. It works by applying the equation eAG (mg/dL) = 28.7 × HbA1c − 46.7, then optionally converting to mmol/L by dividing by 18.0182. The tool also provides interpretation based on whether you have diabetes.

How accurate is the eAG Calculator?

The calculator uses the ADAG formula, which was developed from the largest international study correlating HbA1c with average glucose from continuous glucose monitoring. This formula is the current standard recommended by the American Diabetes Association for converting HbA1c to eAG. The accuracy is excellent for HbA1c values between 4.0% and 12.0%.

What is the difference between HbA1c and eAG?

HbA1c is a percentage that measures the proportion of hemoglobin molecules that have glucose attached. It represents your average blood glucose over the past 2–3 months. eAG is the estimated average glucose in mg/dL or mmol/L, which translates the HbA1c percentage into the same units you see on your daily glucose meter. They are different representations of the same underlying information.

How do I convert HbA1c to eAG?

Multiply your HbA1c percentage by 28.7, then subtract 46.7 to get eAG in mg/dL. To convert to mmol/L, divide the mg/dL value by 18.0182. Our calculator handles the conversion automatically, providing both units instantly.

What is a normal eAG level?

For individuals without diabetes, a normal eAG is below 117 mg/dL (6.5 mmol/L), corresponding to an HbA1c below 5.7%. For people with diabetes, the ADA target is eAG below 154 mg/dL (8.6 mmol/L), corresponding to an HbA1c below 7.0%. Individual targets may vary based on age, comorbidities, and other factors.

Why does the calculator ask if I have diabetes?

The calculator uses your diabetes status to provide appropriate interpretation of your results. The threshold for “normal” differs between those with and without diabetes. For those with diabetes, the target range is below 7.0% (eAG below 154 mg/dL). For those without diabetes, the normal range is below 5.7% (eAG below 117 mg/dL).

Can I use this calculator during pregnancy?

The calculator is based on the ADAG formula validated for adults with and without diabetes. For gestational diabetes, different glucose targets apply, and HbA1c interpretation may differ. Pregnant individuals should consult their healthcare provider for appropriate interpretation of their results.

What if my HbA1c is above 20% or below 3%?

The calculator clamps values to the range of 3.0–20.0% to ensure results remain clinically meaningful. HbA1c values below 3.0% are extremely rare (typically only seen with severe anemia or other conditions affecting red blood cells), and values above 20.0% are beyond typical clinical measurement range.

Is the eAG Calculator suitable for children?

The ADAG formula is valid for adults and has been used in pediatric populations as well. However, for children and adolescents with diabetes, glycemic targets may differ based on age and developmental stage. Consult your pediatric endocrinologist for age-appropriate interpretation.

How often should I check my eAG?

Your eAG is calculated from your HbA1c, which is typically measured every 3–6 months in people with diabetes. You can use this calculator each time you receive an HbA1c result to track changes in your estimated average glucose over time.

Medical Disclaimer

This Estimated Average Glucose (eAG) Calculator is provided for educational and informational purposes only. It does not constitute medical advice, diagnosis, or treatment recommendations. The results are estimates based on the ADAG formula and self-reported information, but they should not replace professional medical evaluation. Always consult with a qualified healthcare provider regarding your diabetes management, glycemic targets, and treatment decisions. No calculator can substitute for proper medical assessment, including individual evaluation of your health status and treatment response.