A1C Calculator
Convert back and forth between your HbA1c percentage and estimated average blood glucose levels.
The Mathematics of HbA1c to Glucose Conversions
HbA1c measures the percentage of your hemoglobin proteins that are coated with sugar (glycated). This correlates directly to average blood glucose levels over the prior 2 to 3 months.
The standard equations derived from the ADAG (A1C-Derived Average Glucose) study are:
Average Glucose (mmol/L) = 1.59 * HbA1c - 2.59
Diabetic Diagnosis Reference Thresholds:
| Status | HbA1c Range | Average Glucose (mg/dL) |
|---|---|---|
| Normal | Under 5.7% | Under 117 mg/dL |
| Prediabetes | 5.7% to 6.4% | 117 to 137 mg/dL |
| Diabetes | 6.5% or higher | 140+ mg/dL |
Frequently Asked Questions
HbA1c stands for Glycated Hemoglobin. When glucose binds to your red blood cells, it forms a glycated bond. Because red blood cells live for approximately 120 days, measuring this percentage provides a stable three-month blood sugar average.
An A1C score of 6.5% or higher on two separate tests is typically diagnostic for diabetes. However, clinical diagnostics must be confirmed by a licensed medical practitioner. Use this tool for reference estimation only.