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Please enter a valid A1C between 3% and 20%.
Primary unit:
eAG (mg/dL)
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eAG (mmol/L)
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What this means
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Related guide
What Is A1C? A Complete Guide
Understand what A1C measures, why it matters for diabetes management, and how your result compares to medical guidelines.
Read the guide →
How to Use This Calculator
1
Choose conversion direction
Select A1C % → eAG if you have your A1C test result, or eAG → A1C % if you're starting from a continuous glucose monitor (CGM) average.
2
Enter your value
Type your A1C percentage (e.g. 7.5) or your eAG in mg/dL or mmol/L. The calculator accepts values in either unit.
3
Read your result
Your estimated average glucose appears instantly — with both mg/dL and mmol/L, a color-coded status, and a plain-English explanation of what it means.
The Formula Behind the Calculator
This calculator uses the formula established by the American Diabetes Association (ADA) based on the ADAG (A1C-Derived Average Glucose) study:
eAG (mg/dL) = (28.7 × A1C%) − 46.7
eAG (mmol/L) = (1.594 × A1C%) − 2.594
Reverse: A1C% = (eAG + 46.7) ÷ 28.7
The ADAG study collected over 2,700 glucose readings per participant across 3 months to validate this relationship. It is the same formula used by the ADA, EASD, and IDF.
A1C Reference Range Chart
This table shows A1C levels, their corresponding eAG values, and the clinical classification used by most healthcare providers:
| A1C % | eAG (mg/dL) | eAG (mmol/L) | Status |
|---|---|---|---|
| 5.0% | 97 | 5.4 | Normal |
| 5.5% | 111 | 6.2 | Normal |
| 5.7% | 117 | 6.5 | Upper Normal |
| 6.0% | 126 | 7.0 | Prediabetes Range |
| 6.5% | 140 | 7.8 | Prediabetes / Diabetes Threshold |
| 7.0% | 154 | 8.6 | Above Target |
| 7.5% | 169 | 9.4 | Above Target |
| 8.0% | 183 | 10.2 | Above Target |
| 9.0% | 212 | 11.8 | High |
| 10.0% | 240 | 13.4 | Very High |
* ADA target for most adults with diabetes: A1C < 7.0% (eAG < 154 mg/dL). Targets vary by individual — discuss with your healthcare provider. Source: NIDDK / NIH.
Worked Example
Here's how the calculation works for a typical A1C result of 7.5%:
Example — A1C 7.5%
eAG (mg/dL) = (28.7 × 7.5) − 46.7
eAG (mg/dL) = 215.25 − 46.7
eAG = 168.6 mg/dL ≈ 169 mg/dL
eAG (mmol/L) = 169 ÷ 18.016
eAG ≈ 9.4 mmol/L
eAG (mg/dL) = 215.25 − 46.7
eAG = 168.6 mg/dL ≈ 169 mg/dL
eAG (mmol/L) = 169 ÷ 18.016
eAG ≈ 9.4 mmol/L
An A1C of 7.5% means your blood sugar has averaged around 169 mg/dL over the past 2–3 months. This is above the ADA target of 7.0% (154 mg/dL) for most adults with diabetes.
Frequently Asked Questions
What is A1C and what does it measure?
A1C (also called HbA1c or glycated hemoglobin) measures the percentage of hemoglobin in your blood that has glucose attached to it. Because red blood cells live for about 2–3 months, your A1C reflects your average blood sugar level over that period — giving a longer-term picture than a single glucose reading.
What is eAG and how is it different from A1C?
eAG stands for estimated Average Glucose. It's A1C translated into the same units (mg/dL or mmol/L) that you see on a home glucose meter or CGM. Many people find eAG easier to relate to because it speaks the same language as daily blood sugar readings. The ADA introduced eAG reporting in 2008 specifically for this reason.
What is a normal A1C level?
For people without diabetes, a normal A1C is below 5.7% (eAG below 117 mg/dL / 6.5 mmol/L). An A1C of 5.7%–6.4% indicates prediabetes. An A1C of 6.5% or higher on two separate tests is typically used to diagnose diabetes. For people already managing diabetes, the ADA recommends an A1C target of below 7.0% (eAG below 154 mg/dL) for most adults, though individual targets vary.
How accurate is this A1C to eAG conversion?
This calculator uses the validated ADAG formula published by the American Diabetes Association, which has a correlation of 0.92 between A1C and eAG in the study population. However, some individuals — including those with certain hemoglobin variants, iron deficiency anemia, or kidney disease — may have A1C results that don't accurately reflect their true average glucose. Always discuss your results with your healthcare provider.
How often should I check my A1C?
The ADA recommends A1C testing at least twice a year for people with stable diabetes who are meeting treatment goals, and quarterly for people whose therapy has changed or who are not meeting goals. People without diabetes but with risk factors should discuss screening frequency with their doctor — often every 1–3 years.
Can I use this calculator if I use mmol/L units?
Yes. This calculator supports both mg/dL (used in the US) and mmol/L (used in the UK, Canada, Australia, and most of Europe). Use the unit toggle to switch your preferred display. The eAG → A1C tab also accepts mmol/L as input.