A1C & Average Glucose Calculator
Use this tool to convert A1C (%) to estimated average glucose (eAG), or convert average glucose back to estimated A1C.
Convert A1C to Estimated Average Glucose
Convert Average Glucose to Estimated A1C
Formula used (ADAG): eAG (mg/dL) = 28.7 × A1C − 46.7. This is an estimate and not a diagnosis.
What this glucose calculator does
If you have ever looked at lab results and wondered how your A1C relates to your day-to-day blood sugar, this calculator helps bridge that gap. A1C reflects your average blood glucose over roughly the last 2 to 3 months. By converting between A1C and average glucose, you can better understand what your trend means in practical terms.
- Convert A1C (%) to estimated average glucose in mg/dL and mmol/L.
- Convert average glucose back to an estimated A1C.
- Get an interpretation category (normal, prediabetes range, diabetes range).
How to use this calculator
1) If you know your A1C
Enter your A1C value (for example, 5.8, 6.4, or 7.2) and click Calculate from A1C. You will see:
- Estimated average glucose in mg/dL
- Estimated average glucose in mmol/L
- A general interpretation category
2) If you track average glucose at home
Enter your average glucose and select units (mg/dL or mmol/L), then click Calculate from Glucose. The tool will estimate your A1C and show the corresponding glucose value in both units.
A1C reference ranges (general guideline)
| A1C Range | Interpretation | Estimated Average Glucose (mg/dL) |
|---|---|---|
| Below 5.7% | Typical (non-diabetes range) | Below ~117 |
| 5.7% to 6.4% | Prediabetes range | ~117 to ~137 |
| 6.5% or higher | Diabetes range | ~140 and up |
Why A1C and fingerstick/CGM numbers can look different
It is common for people to feel confused when one number seems “good” and another seems “off.” A few reasons:
- A1C is a long-term average, while meter/CGM values are moment-to-moment.
- Red blood cell lifespan differences can affect A1C accuracy.
- Anemia, kidney disease, pregnancy, and some hemoglobin variants may alter A1C results.
- Recent changes in diet, medication, or activity may not fully show in A1C yet.
How to improve A1C over time
Small, consistent habits usually outperform extreme short-term plans. Useful strategies include:
- Build meals around fiber, protein, and minimally processed carbohydrates.
- Take a short walk after meals to help reduce post-meal glucose spikes.
- Track patterns: fasting, post-meal, sleep, stress, and exercise response.
- Review medications with your clinician on a regular schedule.
- Protect sleep quality and stress management—both directly affect glucose control.
Frequently asked questions
Is this calculator diagnostic?
No. It provides estimates based on established formulas. Diagnosis requires clinical evaluation and lab testing.
What is a common A1C goal?
Many adults with diabetes are advised to target around 7% or lower, but individual goals vary by age, risk profile, comorbidities, and clinician guidance.
Should I use mg/dL or mmol/L?
Use whichever unit your meter, lab report, or country standard uses. This calculator supports both and converts automatically.
Medical disclaimer
This page is for educational purposes only and does not replace personalized medical advice. If your glucose values are frequently high or low, contact a qualified healthcare professional.