Calculate A1C and average blood sugar with the ADAG formula. See your diabetes risk category and eAG in mg/dL or mmol/L instantly.
Medical Disclaimer
This calculator is for educational purposes only and should not replace professional medical advice. Always consult your healthcare provider for A1C testing and diabetes management.
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The A1C test (also called HbA1c or hemoglobin A1C) measures your average blood sugar over the past 2-3 months. This calculator helps you convert between A1C percentage and estimated average glucose (eAG) using the ADAG formula. Whether you're tracking diabetes management, monitoring prediabetes, or simply curious about your blood sugar trends, understanding your A1C is essential for long-term health.
A1C, short for hemoglobin A1C (HbA1c), measures the percentage of your red blood cells that have glucose attached to them. Since red blood cells live for about 3 months, A1C provides a picture of your average blood sugar levels over that period. Unlike daily finger-stick readings that capture a single moment, A1C shows the bigger picture of your glucose control.
ADAG Formula
eAG (mg/dL) = 28.7 × A1C − 46.7Convert A1C to average glucose OR average glucose to estimated A1C.
See immediately if you're in normal, prediabetes, or diabetes range.
Understand the ADAG calculation process with detailed math steps.
Switch between mg/dL (US) and mmol/L (international) glucose units.
Uses the official ADA-endorsed ADAG equation from peer-reviewed research.
Color-coded gauge shows exactly where your A1C falls in the health spectrum.
Track your A1C progress between lab tests and understand what your results mean.
Understand your risk level and set targets for lifestyle changes.
Compare your continuous glucose monitor averages to estimated A1C.
Estimate your A1C before doctor visits to prepare questions.
Convert between mg/dL (US) and mmol/L (international) units easily.
Learn the ADAG formula and understand how A1C relates to daily blood sugar.
A normal A1C is below 5.7%. This indicates healthy blood sugar control. Between 5.7% and 6.4% is considered prediabetes, and 6.5% or higher indicates diabetes.
Use the reverse ADAG formula: A1C = (Average Glucose in mg/dL + 46.7) ÷ 28.7. For example, an average glucose of 154 mg/dL gives: (154 + 46.7) ÷ 28.7 = 7.0% A1C.
A1C stands for Hemoglobin A1C (also written HbA1c). The 'A1C' refers to a specific type of glycated hemoglobin where glucose binds to the hemoglobin in your red blood cells.
An A1C of 6.5% or higher is the diagnostic threshold for diabetes according to the American Diabetes Association. This corresponds to an average blood sugar of about 140 mg/dL.
No, fasting is not required for an A1C test. Since it measures your average blood sugar over 2-3 months, a single meal won't affect the result.
Your meter captures point-in-time readings (often before meals when blood sugar is lower), while A1C reflects all 24 hours including after-meal spikes. Also, the A1C formula is weighted toward more recent glucose levels.
eAG (estimated Average Glucose) is your average blood sugar level in mg/dL or mmol/L, calculated from your A1C using the ADAG formula. It helps you understand what your A1C means in everyday blood sugar terms.
Yes, lifestyle changes can lower A1C: balanced diet, regular exercise, weight management, stress reduction, and adequate sleep. A 1-point reduction in A1C significantly reduces diabetes complications.
The ADAG (A1C-Derived Average Glucose) formula is: eAG (mg/dL) = 28.7 × A1C − 46.7. It was established by a major study published in Diabetes Care in 2008 and is endorsed by the ADA.
Yes, certain conditions can affect A1C accuracy including anemia, hemoglobin variants, recent blood transfusions, pregnancy, and kidney or liver disease. In these cases, consult your healthcare provider for alternative tests.
The ADA recommends A1C testing at least twice a year if meeting treatment goals, or quarterly if treatment has changed or you're not meeting targets.
Blood glucose is a snapshot of your blood sugar at one moment in time. A1C is a 3-month average. Daily glucose readings vary widely throughout the day, while A1C provides a stable measure of overall control.