A1C to Blood Sugar Calculator
Convert A1C percentage to estimated average glucose (eAG) in mg/dL and mmol/L.
See how your A1C compares to normal, prediabetes, and diabetes ranges.
A1C (also called HbA1c or glycated hemoglobin) is a blood test that reflects your average blood sugar level over the past 2-3 months. It works by measuring the percentage of hemoglobin proteins in your red blood cells that have glucose attached to them.
The conversion formula (developed by the ADAG study):
eAG (mg/dL) = (28.7 × A1C) - 46.7
eAG (mmol/L) = eAG (mg/dL) / 18.0
What the variables mean:
- A1C (%) — the percentage from your lab test result
- eAG — estimated Average Glucose, the daily blood sugar level your A1C corresponds to
- mg/dL — milligrams per deciliter, the unit used in the US, Japan, and several other countries
- mmol/L — millimoles per liter, the unit used in the UK, Canada, Australia, and most of Europe
A1C interpretation ranges (per ADA guidelines):
| A1C Level | Category | Estimated Avg Glucose |
|---|---|---|
| Below 5.7% | Normal | Below 117 mg/dL (6.5 mmol/L) |
| 5.7% - 6.4% | Prediabetes | 117-137 mg/dL (6.5-7.6 mmol/L) |
| 6.5% or higher | Diabetes | 140+ mg/dL (7.8+ mmol/L) |
Practical example: An A1C of 7.0% converts to eAG = (28.7 × 7.0) - 46.7 = 154 mg/dL (8.6 mmol/L). This is a common target for adults managing diabetes.
Tips: A1C is typically tested every 3-6 months. Results can be affected by conditions like anemia, kidney disease, or recent blood transfusions. Always discuss your A1C results with your healthcare provider, as individual targets may vary based on age, health history, and other factors.