A1c to Blood Glucose Calculator
Convert A1C percentage to estimated average blood glucose (eAG) in mg/dL or mmol/L. Enter values for instant results with step-by-step formulas.
Formula
eAG (mg/dL) = 28.7 x A1C - 46.7
The ADAG (A1C-Derived Average Glucose) formula converts A1C percentage to estimated average glucose. This linear regression equation was derived from a multicenter study comparing A1C values with continuous glucose monitoring data. To convert to mmol/L, divide the mg/dL result by 18.0182. For example, an A1C of 7% yields eAG = 28.7 x 7 - 46.7 = 154.2 mg/dL or 8.6 mmol/L.
Worked Examples
Example 1: Prediabetes Assessment
Problem: A patient has an A1C of 6.0%. Convert to estimated average glucose and assess diabetes risk category.
Solution: eAG (mg/dL) = 28.7 x 6.0 - 46.7 = 172.2 - 46.7 = 125.5 mg/dL\neAG (mmol/L) = 125.5 / 18.0182 = 7.0 mmol/L\nA1C of 6.0% falls in the prediabetes range (5.7-6.4%)\nThe patient has elevated glucose and increased diabetes risk
Result: eAG: 125.5 mg/dL (7.0 mmol/L) | Category: Prediabetes | Action: Lifestyle changes recommended
Example 2: Diabetes Management Check
Problem: A type 2 diabetes patient has an A1C of 8.2%. Calculate eAG and determine how far from the target of 7.0%.
Solution: eAG (mg/dL) = 28.7 x 8.2 - 46.7 = 235.3 - 46.7 = 188.7 mg/dL\neAG (mmol/L) = 188.7 / 18.0182 = 10.5 mmol/L\nTarget A1C = 7.0%, Target eAG = 154.2 mg/dL\nReduction needed = 8.2 - 7.0 = 1.2% A1C\nGlucose reduction needed = 188.7 - 154.2 = 34.4 mg/dL
Result: eAG: 188.7 mg/dL | 1.2% above target | Need to reduce average glucose by 34.4 mg/dL
Frequently Asked Questions
What is A1C and how does it differ from regular blood glucose readings?
A1C (also called hemoglobin A1C, HbA1c, or glycated hemoglobin) measures the percentage of hemoglobin in your red blood cells that has glucose attached to it. Since red blood cells live approximately 120 days, A1C provides a weighted average of your blood glucose levels over the past 2-3 months, with more recent weeks weighted more heavily. Regular blood glucose readings from finger sticks or continuous glucose monitors show your glucose at a single moment in time and can fluctuate dramatically based on meals, exercise, stress, and medications. A1C gives the broader picture of glucose management that single readings cannot capture, which is why it is the primary test used to diagnose diabetes and monitor long-term glycemic control.
What is estimated Average Glucose (eAG) and how is it calculated?
Estimated Average Glucose (eAG) is a way to express A1C results in the same units used by blood glucose meters, making it easier for patients to relate A1C to their daily glucose readings. The conversion formula is eAG (mg/dL) = 28.7 multiplied by A1C minus 46.7, which was derived from the ADAG (A1C-Derived Average Glucose) study that compared A1C with continuous glucose monitoring data from over 500 participants. For metric units, divide the mg/dL result by 18.0182 to get mmol/L. For example, an A1C of 7% corresponds to an eAG of approximately 154 mg/dL or 8.6 mmol/L. This translation helps patients understand what their A1C number means in practical, everyday terms.
How does A1C relate to daily blood glucose monitoring?
A1C and daily blood glucose monitoring provide complementary information about glycemic control. Daily monitoring shows real-time glucose values and helps identify patterns, highs, and lows throughout the day, while A1C reflects the overall average over months. Two patients with identical A1C values can have very different daily glucose patterns: one may have stable readings close to the average, while another swings between dangerous highs and lows that average out the same. This is why Time in Range, the percentage of time glucose stays between 70-180 mg/dL as measured by continuous glucose monitors, is becoming an important complementary metric. Most diabetes management plans use both A1C for long-term assessment and daily monitoring for immediate adjustment.
Is my data stored or sent to a server?
No. All calculations run entirely in your browser using JavaScript. No data you enter is ever transmitted to any server or stored anywhere. Your inputs remain completely private.
Can I share or bookmark my calculation?
You can bookmark the calculator page in your browser. Many calculators also display a shareable result summary you can copy. The page URL stays the same so returning to it will bring you back to the same tool.
How do I interpret the result?
Results are displayed with a label and unit to help you understand the output. Many calculators include a short explanation or classification below the result (for example, a BMI category or risk level). Refer to the worked examples section on this page for real-world context.