A1C Calculator
Convert between A1C and average blood glucose. See diabetes risk classification.
Your A1C
5.7%
Prediabetes
Estimated Avg. Glucose
117 mg/dL
Avg. Glucose (mmol/L)
6.5
A1C Categories
| Normal | < 5.7% |
| Prediabetes | 5.7% – 6.4% |
| Diabetes | ≥ 6.5% |
A1C to Average Glucose Reference
| 5.0% | 97 mg/dL |
| 5.5% | 111 mg/dL |
| 6.0% | 126 mg/dL |
| 6.5% | 140 mg/dL |
| 7.0% | 154 mg/dL |
| 8.0% | 183 mg/dL |
| 9.0% | 212 mg/dL |
A1C reflects average blood glucose over the past 2–3 months. Formula: eAG (mg/dL) = 28.7 × A1C − 46.7. Individual results may vary. Consult your healthcare provider for diagnosis and treatment.
Use the A1C Calculator above to calculate your results. Enter your values and see instant results — all calculations run in your browser.
Disclaimer: This calculator is for informational purposes only and does not constitute tax, financial, or legal advice. Results are estimates based on the information you provide and current rates. Always consult a qualified tax professional or financial advisor for advice specific to your situation.
How It Works
Our A1C Calculator helps you effortlessly convert your A1C percentage into an estimated average blood glucose (eAG) in mg/dL or mmol/L, and vice-versa. Understanding this conversion is crucial for managing diabetes effectively and for early detection of prediabetes, as it provides a clearer picture of your long-term blood sugar control beyond daily fluctuations. With the latest 2026 health guidelines emphasizing proactive management, this tool empowers you to track your progress and discuss your results confidently with your healthcare provider.
The conversion between A1C and eAG is based on a standardized formula derived from extensive research involving multiple studies. The formula used is eAG (mg/dL) = 28.7 × A1C - 46.7, or eAG (mmol/L) = 1.59 × A1C - 2.59. This equation provides a statistically robust estimate of your average blood glucose over the past 2-3 months, reflecting the average glucose attached to your red blood cells.
While highly useful, remember that eAG is an estimate and individual variations can occur due to factors like red blood cell lifespan or certain medical conditions. Do not use this calculator as a substitute for professional medical advice or to self-diagnose; always consult your doctor for accurate interpretation of your A1C results and for personalized treatment plans. A common mistake is to only focus on a single A1C reading without considering trends over time or the impact of lifestyle changes.
Example: Understanding a Prediabetes Diagnosis
- 1 Sarah's doctor informed her in early 2026 that her A1C was 5.9%. Concerned about her risk for diabetes, she uses this calculator to understand what that means for her average blood glucose.
- 2 Using the calculator, Sarah inputs her A1C of 5.9%. The calculator then applies the formula: eAG (mg/dL) = 28.7 × 5.9 - 46.7.
- 3 The calculator outputs an estimated average blood glucose (eAG) of 122.3 mg/dL (or 6.8 mmol/L).
- 4 This eAG of 122.3 mg/dL places Sarah in the prediabetes category (eAG between 100-125 mg/dL, or 5.6-6.9 mmol/L), aligning with her A1C of 5.9% (prediabetes is 5.7-6.4%). This information prompts her to discuss lifestyle changes with her doctor to prevent type 2 diabetes.
Source: CDC · Last updated: April 2026
Frequently Asked Questions
What A1C level is considered diabetic?
What does A1C measure exactly?
How quickly can I lower my A1C?
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