A1C Calculator and A1C Chart: Convert A1C to Average Blood Sugar

Your A1C test result is a percentage, but it’s easier to understand as an average blood sugar number, the kind you’d see on a glucose meter. This free A1C calculator converts your A1C to estimated average glucose (eAG), or works the other way, from average blood sugar to A1C.

Below the calculator you’ll find a full A1C chart and what each range means.

A1C Calculator

Convert your A1C to estimated average glucose (eAG), or your average blood sugar to an estimated A1C.

Please enter a realistic value (A1C between 3% and 20%).

Uses the ADAG formula: eAG (mg/dL) = 28.7 × A1C − 46.7. This tool is for information only and can’t diagnose diabetes or prediabetes.

What Is A1C?

The A1C test (also called HbA1c or glycated hemoglobin) measures the percentage of your red blood cells that have sugar attached to them. Because red blood cells live for about three months, A1C reflects your average blood sugar over the past 2 to 3 months, not just one day.

A1C Ranges

A1CWhat it means
Below 5.7%Normal range
5.7% to 6.4%Prediabetes range
6.5% or higherDiabetes range

Source: CDC and American Diabetes Association. A diagnosis is usually confirmed with a repeat test or another type of blood sugar test.

A1C Chart: A1C to Average Blood Sugar

A1C (%)Estimated average glucose (mg/dL)(mmol/L)
4.0683.8
4.5824.6
5.0975.4
5.51116.2
5.71176.5
6.01257.0
6.51407.8
7.01548.6
7.51699.4
8.018310.2
8.519710.9
9.021211.7
9.522612.5
10.024013.3
11.026914.9
12.029816.5
13.032618.1
14.035519.7

How the A1C Calculator Works

The calculator uses the formula from the A1C-Derived Average Glucose (ADAG) study, the same one used by the American Diabetes Association:

eAG (mg/dL) = 28.7 × A1C − 46.7

To convert mg/dL to mmol/L, divide by about 18.

Why A1C and Meter Readings Don't Always Match

Your A1C is an average over months, while a meter reading is one moment in time. They can differ because of:

  • Timing: meter checks often happen before meals, when sugar is lower
  • Anemia or iron deficiency, which can affect A1C results. See iron deficiency or perimenopause
  • Some kidney or liver conditions, recent blood loss, or pregnancy
  • Certain hemoglobin variants, more common in some ethnic groups

If your A1C doesn't seem to match your daily readings, ask your doctor.

Blood Sugar After 40 and Menopause

Risk of type 2 diabetes rises with age. For women, the menopause transition can bring changes in weight distribution, especially more weight around the waist, along with poorer sleep, both of which can affect blood sugar. Helpful steps include:

How Often Should You Get an A1C Test?

That depends on your results and health. Adults are commonly screened from age 35, or earlier with risk factors such as overweight, family history, or a history of gestational diabetes. If your results are normal, testing is often repeated every 3 years. With prediabetes, it's often checked every 1 to 2 years. People with diabetes are usually tested at least twice a year. Your doctor will advise what's right for you.

When to See a Doctor

See a doctor if:

  • Your A1C is 5.7% or higher
  • You have symptoms like increased thirst, frequent urination, blurry vision, slow-healing sores, or unexplained weight loss
  • You have risk factors and haven't been tested

Get urgent care for very high blood sugar with vomiting, confusion, or trouble breathing.

Frequently Asked Questions

What is a normal A1C?
Below 5.7%.

What A1C is prediabetes?
5.7% to 6.4%.

What blood sugar is an A1C of 7?
About 154 mg/dL (8.6 mmol/L).

What does an A1C of 6 mean?
6.0% is in the prediabetes range and equals an estimated average glucose of about 125 mg/dL.

Can this calculator diagnose diabetes?
No. Only a doctor can diagnose diabetes, usually with repeat testing.

What A1C target should I aim for if I have diabetes?
Many adults with diabetes aim for below 7%, but targets are personal. Your doctor will set the right goal for you.

Related Tools

This calculator is for general information only and is not medical advice. It can't diagnose diabetes or prediabetes. Read our Medical Disclaimer and Editorial Policy.

Sources

Health note: Content on this site is for general information only and is not medical advice. Always consult your doctor about health concerns.

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