About A1C Calculator

Understanding A1C and blood glucose management

What is A1C?

A1C (Hemoglobin A1c or HbA1c) is a blood test that measures your average blood glucose levels over the past 2-3 months. It shows the percentage of hemoglobin that has glucose attached to it.

Unlike daily blood glucose tests that show your levels at a specific moment, A1C provides a broader picture of your blood glucose control over time.

A1C is the gold standard for monitoring long-term diabetes management and is used for diagnosis and treatment decisions.

A1C Reference Ranges

Normal
< 5.7%

Low risk of diabetes

Prediabetes
5.7% - 6.4%

High risk of developing diabetes

Diabetes
≥ 6.5%

Diabetes diagnosis

Estimated Average Glucose (eAG)

eAG translates your A1C result into the same units (mg/dL or mmol/L) as your daily glucose meter readings. This helps you better understand your A1C result.

The eAG calculation is based on data from the A1C-Derived Average Glucose (ADAG) study, which involved continuous glucose monitoring in people with diabetes.

Calculation Formula:

EAG (mg/dL) = 28.7 × A1C - 46.7

How to Use This Calculator

A1C to Average Glucose

Enter your A1C percentage (typically between 4.0% and 20.0%) to see your estimated average glucose in both mg/dL and mmol/L units.

Average Glucose to A1C

Enter your average glucose reading in either mg/dL or mmol/L to estimate what your A1C percentage might be.

Scientific References

1. A1C-Derived Average Glucose (ADAG) Study

Nathan DM, Kuenen J, Borg R, et al. Translating the A1C assay into estimated average glucose values.Diabetes Care. 2008;31(8):1473-1478.

DOI: 10.2337/dc08-0545

|View Paper

2. American Diabetes Association Standards of Care

American Diabetes Association. Standards of Medical Care in Diabetes—2023.Diabetes Care. 2023;46(Supplement_1):S1-S291.

DOI: 10.2337/dc23-Sint

|View Paper

3. World Health Organization Diagnostic Criteria

World Health Organization. Use of glycated haemoglobin (HbA1c) in the diagnosis of diabetes mellitus: abbreviated report of a WHO consultation. Geneva: World Health Organization; 2011.

WHO/NMH/CHP/CPM/11.1

|View Paper

4. Diabetes Control and Complications Trial (DCCT)

The Diabetes Control and Complications Trial Research Group. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus.New England Journal of Medicine. 1993;329(14):977-986.

DOI: 10.1056/NEJM199309303291401

|View Paper

5. UK Prospective Diabetes Study (UKPDS)

UK Prospective Diabetes Study (UKPDS) Group. Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33).The Lancet. 1998;352(9131):837-853.

DOI: 10.1016/S0140-6736(98)07019-6

|View Paper

These references represent landmark studies and authoritative guidelines that form the scientific foundation for A1C testing and diabetes management recommendations.

A1C Calculator: Track Your Diabetes Progress & Stay Healthy