A1C to eAG Converter

Convert between HbA1c (%) and estimated average glucose (mg/dL & mmol/L) using the ADAG study formula. Assess glycemic control, understand diabetes risk categories, and visualize your results on an interactive A1C scale. Trusted by clinicians, educators, and patients worldwide.

% (NGSP)
Typical range: 4.0% – 15.0%. Lower values indicate better long‑term glucose control.
mg/dL
Alternative unit: mmol/L result shown below. Formula: 28.7 × A1C – 46.7 (ADAG).
? eAG (mmol/L): — mmol/L
? Glycemic status: —
? Normal: A1C 5.7%
⚠️ Prediabetes: 6.2%
? Diabetes target: 7.0%
? Elevated: 8.5%
⚠️ High risk: 10.0%
Clinically informed & privacy-first: All calculations are performed locally in your browser. This tool is for educational use; always consult a physician or certified diabetes care specialist for medical decisions.
Your A1C Interpretation & Visualization
Normal (<5.7%)
Prediabetes (5.7–6.4%)
Diabetes (≥6.5%)
Your A1C
A1C = 5.7 %
eAG = 117 mg/dL
eAG = 6.5 mmol/L
Clinical range: Normal / Low risk
ADA recommendation: Most non‑pregnant adults with diabetes target A1C <7.0%

Understanding A1C and Estimated Average Glucose

HbA1c (glycated hemoglobin) reflects your average blood glucose levels over the past 2–3 months. The estimated average glucose (eAG) translates the A1C percentage into daily glucose units (mg/dL or mmol/L), making it easier for patients to correlate with routine self‑monitoring. The conversion is based on the international ADAG study (Nathan et al., 2008) and endorsed by the American Diabetes Association (ADA).

ADAG linear regression formula:

eAG (mg/dL) = 28.7 × A1C (%) – 46.7

eAG (mmol/L) = (28.7 × A1C – 46.7) ÷ 18.016   or   1.59 × A1C – 2.59

Correlation coefficient r = 0.92, providing strong clinical validity.

Why A1C Matters in Diabetes Management

  • Long‑term monitoring: Unlike daily fingersticks, A1C reveals overall glycemic control and predicts complication risks (retinopathy, nephropathy).
  • Treatment targets: The ADA recommends A1C <7.0% for most non‑pregnant adults with diabetes. Less stringent goals (e.g., <8.0%) may apply to older adults or those with severe hypoglycemia.
  • Prediabetes screening: A1C between 5.7% and 6.4% indicates prediabetes – a critical window for lifestyle interventions.
  • Standardized worldwide: HbA1c is measured using NGSP/IFCC certified methods, ensuring reliable comparisons.

How to Interpret Your Result

A1C % eAG (mg/dL) eAG (mmol/L) Interpretation
< 5.7% < 117 < 6.5 Normal – No diabetes
5.7% – 6.4% 117 – 137 6.5 – 7.6 Prediabetes – Increased risk; lifestyle changes recommended
≥ 6.5% ≥ 140 ≥ 7.8 Diabetes – Consult your healthcare provider for treatment plan
≥ 8.0% ≥ 183 ≥ 10.2 Suboptimal control – Therapy intensification often needed
Clinical Case Example

A 52‑year‑old patient with type 2 diabetes presents an A1C of 8.2% (eAG ≈ 189 mg/dL). Using our converter, the clinician immediately visualizes that average glucose exceeds the ADA target. The patient’s medication regimen (metformin + SGLT2 inhibitor) is intensified, and after 3 months the A1C decreases to 7.1% – significantly reducing microvascular risk.

ADAG Study: The Scientific Foundation

The A1C-Derived Average Glucose (ADAG) study involved 507 participants (268 with type 1 diabetes, 159 with type 2, 80 non‑diabetic) across 10 international centers. Continuous glucose monitoring (CGM) was used to calculate average glucose, then linear regression established the robust formula: eAG (mg/dL) = 28.7 × A1C – 46.7. The high correlation (R² = 0.84) confirms that A1C reliably predicts average glucose.

Source: Nathan DM, Kuenen J, Borg R, et al. “Translating the A1C assay into estimated average glucose values.” Diabetes Care. 2008;31(8):1473‑1478.

Frequently Asked Questions

A1C provides a 2–3 month average, while daily fingersticks show real‑time glucose. Use both for complete glycemic assessment.

A1C targets in pregnancy differ (often <6.0%). Please follow your obstetrician’s specific guidelines – the converter provides general estimation only.

Conditions like anemia, hemoglobin variants, or kidney failure can interfere. Always discuss anomalies with a physician.

Yes. Both eAG values (mg/dL and mmol/L) are displayed simultaneously. No extra steps needed.

ADA recommends at least twice yearly in stable patients, quarterly if therapy changed or not meeting goals.

Endorsed by clinical evidence – This tool implements the ADAG formula and ADA classification thresholds. Updated June 2026. For personalized therapy, always refer to your healthcare provider.

References: American Diabetes Association. “6. Glycemic Targets: Standards of Medical Care in Diabetes—2025.”; Nathan et al., Diabetes Care 2008; International Expert Committee Report, 2009.