A1C Calculator
Convert between A1C percentage and estimated average blood glucose (eAG) using the ADA formula, and see your diabetes risk category instantly.
How to use this calculator
Choose your conversion direction using the toggle: "A1C → Blood Sugar" converts a known A1C percentage to estimated average glucose, while "Blood Sugar → A1C" works in reverse. Adjust the slider to your value. Your A1C, eAG in mg/dL and mmol/L, and ADA diabetes category all update instantly. Results reflect the ADA/ADAG equation validated in a multi-ethnic study of 507 adults.
Understanding your A1C results
A1C is expressed as a percentage of glycated hemoglobin. The ADA diagnostic thresholds are: below 5.7% = normal, 5.7–6.4% = prediabetes, 6.5% or above = diabetes. For people already diagnosed with diabetes, the typical management target is below 7.0%, though individual targets may vary based on age, hypoglycemia risk, and other factors. The estimated average glucose (eAG) translates A1C into the same units as home blood glucose meters, making it easier to understand day-to-day.
Frequently asked questions
A1C to average blood glucose conversion table
Use this table to see how any A1C percentage corresponds to an estimated average blood glucose (eAG) in both mg/dL (US) and mmol/L (international units). The formula used is the ADA/ADAG equation: eAG(mg/dL) = 28.7 × A1C − 46.7.
| A1C (%) | eAG (mg/dL) | eAG (mmol/L) |
|---|---|---|
| 5.0% | 97 mg/dL | 5.4 mmol/L |
| 5.5% | 111 mg/dL | 6.2 mmol/L |
| 6.0% | 125 mg/dL | 7.0 mmol/L |
| 6.5% | 140 mg/dL | 7.8 mmol/L |
| 7.0% | 154 mg/dL | 8.6 mmol/L |
| 7.5% | 169 mg/dL | 9.4 mmol/L |
| 8.0% | 183 mg/dL | 10.2 mmol/L |
| 8.5% | 197 mg/dL | 11.0 mmol/L |
| 9.0% | 212 mg/dL | 11.8 mmol/L |
| 9.5% | 226 mg/dL | 12.6 mmol/L |
| 10.0% | 240 mg/dL | 13.4 mmol/L |
| 10.5% | 255 mg/dL | 14.1 mmol/L |
| 11.0% | 269 mg/dL | 14.9 mmol/L |
| 11.5% | 283 mg/dL | 15.7 mmol/L |
| 12.0% | 298 mg/dL | 16.5 mmol/L |
| 12.5% | 312 mg/dL | 17.3 mmol/L |
| 13.0% | 326 mg/dL | 18.1 mmol/L |
| 13.5% | 341 mg/dL | 18.9 mmol/L |
| 14.0% | 355 mg/dL | 19.7 mmol/L |
What A1C measures
Hemoglobin A1C (HbA1c) measures the percentage of hemoglobin proteins in red blood cells that have glucose attached to them. Because red blood cells live approximately 90–120 days, A1C reflects average blood sugar levels over the past 2–3 months — not just a single snapshot like a fasting glucose test. Important limitations: A1C can be falsely low in conditions that shorten red blood cell lifespan (hemolytic anemia, significant blood loss, recent transfusion). It can be falsely high in iron deficiency anemia or with certain hemoglobin variants. Kidney disease, liver disease, and pregnancy also affect results. A1C should always be interpreted alongside other clinical findings.
How to lower your A1C
A1C typically responds to sustained changes in blood sugar control over 2–3 months. These evidence-based strategies are recommended by the American Diabetes Association.
- ·Reduce refined carbohydrates and added sugars — these cause the largest post-meal glucose spikes and drive A1C up over time
- ·Follow a consistent meal schedule — eating at regular intervals helps prevent blood sugar swings that elevate average glucose
- ·Increase physical activity — both aerobic exercise and resistance training independently improve insulin sensitivity and lower glucose
- ·Lose excess body weight — even 5–10% body weight reduction significantly improves blood sugar control in people with prediabetes or diabetes
- ·Take medications as prescribed — missing doses of metformin, insulin, or other diabetes medications allows blood sugar to rise between checks
- ·Monitor blood glucose regularly — self-monitoring reveals patterns that allow you and your provider to adjust diet, activity, or medications proactively
- ·Prioritize sleep — poor sleep (under 6 hours or fragmented) raises cortisol and growth hormone levels that antagonize insulin action
- ·Manage stress — chronic psychological stress activates the HPA axis, elevating cortisol and directly raising blood glucose levels
Symptoms of high and low blood sugar
Recognizing symptoms of hyperglycemia and hypoglycemia is important for anyone managing diabetes or prediabetes.
| Hyperglycemia (High Blood Sugar) | Hypoglycemia (Low Blood Sugar) |
|---|---|
| Frequent urination | Shakiness or trembling |
| Increased thirst | Sweating |
| Blurred vision | Rapid heartbeat |
| Fatigue or lack of energy | Irritability or mood changes |
| Headache | Dizziness or lightheadedness |
| Slow-healing wounds | Confusion or difficulty concentrating |
| Frequent infections | Hunger even after eating |
| Nausea in severe cases | Loss of consciousness (severe cases) |