A1C to Glucose Calculator

Convert HbA1c to estimated average glucose (eAG) in mg/dL or mmol/L. Includes reverse eAG to A1C conversion, ADA diagnostic bands, CGM time-in-range correlation, and diabetes type-specific targets.

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Estimated Average Glucose (mg/dL)
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eAG (mmol/L) —
ADA Diagnostic Category —
Extended More scenarios, charts & detailed breakdown ▾
%
eAG (mg/dL)
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eAG (mmol/L) —
ADA Category —
Professional Full parameters & maximum detail ▾
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%
eAG (mg/dL)
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ADA A1C Target for Population —
GMI from TIR (approx A1C equiv) —
Clinical Note —

How to Use This Calculator

  1. Enter your HbA1c percentage from your lab report.
  2. Results instantly show eAG in mg/dL, mmol/L, and the ADA diagnostic category.
  3. Use eAG to A1C to reverse-calculate from average glucose to expected A1C.
  4. Use ADA Bands for full clinical interpretation and targets.
  5. Use Professional for CGM time-in-range correlation and diabetes-type-specific targets.

Formula

eAG (mg/dL) = 28.7 x A1C(%) - 46.7

eAG (mmol/L) = eAG (mg/dL) / 18.018. Reverse: A1C(%) = (eAG + 46.7) / 28.7.

Example

Example: A1C = 7.5%. eAG = 28.7 x 7.5 - 46.7 = 215.25 - 46.7 = 168.6 mg/dL (9.36 mmol/L). Category: Diabetes - Above Target.

Frequently Asked Questions

  • The ADA/ADAG study formula: eAG (mg/dL) = 28.7 x A1C(%) - 46.7. For example, an A1C of 7.0% corresponds to an eAG of about 154 mg/dL. In mmol/L, divide by 18.018.
  • ADA 2026 Standards: Normal < 5.7%, Prediabetes 5.7-6.4%, Diabetes >= 6.5% on two separate tests. A1C >= 6.5% on a single test with classic symptoms is also diagnostic.
  • The ADA recommends < 7.0% for most non-pregnant adults with diabetes. Targets may be relaxed to < 8.0% for older adults, patients with severe hypoglycemia history, or limited life expectancy.
  • Glucose Management Indicator (GMI) is an A1C estimate derived from CGM data: GMI(%) = 3.31 + 0.02392 x mean glucose (mg/dL). GMI and laboratory A1C can differ by 0.3-0.5% due to individual red blood cell turnover differences.
  • A1C is unreliable in: hemoglobinopathies (sickle cell, thalassemia), severe anemia (falsely low), recent blood transfusion (falsely low), and conditions with altered red blood cell turnover. In these cases, use fructosamine or CGM time-in-range.

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Sources & References (5) ▾
  1. ADA Standards of Medical Care in Diabetes — 2026 — American Diabetes Association
  2. Nathan DM et al. (2008) — Translating the A1C Assay into Estimated Average Glucose Values (ADAG Study), Diabetes Care — Diabetes Care / ADA
  3. NIDDK — A1C Test for Diabetes — NIH / NIDDK
  4. AACE/ACE Guidelines for Management of Type 2 Diabetes — Endocrine Practice / AACE
  5. Endocrine Society — Diabetes Management Clinical Practice Guideline — Endocrine Society