A1c Calculator

The percentage on a US-style report. Values outside 3-20% are rejected as unit mix-ups.
Used in the glucose-to-A1c direction. Accepted range 40-600 mg/dL (2.2-33.3 mmol/L).
The whole-number figure on UK, European and Australian reports (e.g. 53 mmol/mol = 7.0%).
ADAG is what the ADA, NGSP and every current eAG table use. DCCT 2002 is the older type 1-only regression; it gives about 10% higher glucose values.
Estimated average glucose
154 mg/dL
A1c to Average Glucose (eAG) Calculator
Estimated average glucose
8.6 mmol/L
eAG by the published mmol/L line (secondary)
8.5 mmol/L
A1c (NGSP)
7.0 %
A1c (IFCC)
53 mmol/mol
ADA range (for information, not diagnosis)
In the diabetes range (A1c >= 6.5%, >= 48 mmol/mol)
eAG before rounding
154.200 mg/dL
Regression used
ADAG (Nathan 2008) - ADA/NGSP standard
Worked out from Nathan DM, Kuenen J, Borg R, Zheng H, Schoenfeld D, Heine RJ; A1c-Derived Average Glucose Study Group. Translating the A1C assay into estimated average glucose values. Diabetes Care 2008;31(8):1473-1478 and 7 other sources.
The published mmol/L line gives 8.5 rather than 8.6 mmol/L. The difference is coefficient rounding (1.59 and 2.59 are 28.7/18 and 46.7/18 rounded), not a different model; the published tables agree with 8.6.
The classification is for information only. Diagnosis requires an NGSP-certified assay and confirmatory testing, and the ADA says to use plasma glucose criteria instead where the A1c-glucose relationship is altered: hemoglobin variants, pregnancy (2nd/3rd trimester and postpartum), G6PD deficiency, HIV, hemodialysis, recent blood loss or transfusion, hemolysis, anemia or erythropoietin therapy.
eAG is a population estimate with wide 95% confidence intervals (ADAG: A1c 7% -> 123-185 mg/dL); an individual's true mean glucose can differ substantially.
For information only, not diagnosis. eAG is a population regression with wide confidence intervals (A1c 7% corresponds to 123-185 mg/dL), and the ADA requires an NGSP-certified assay and confirmatory testing before diagnosing diabetes.

How this is worked out

6 steps
  1. A1c entered = 7% (NGSP)
  2. eAG (mg/dL) = 28.7 x 7 - 46.7 = 154.2 -> 154 mg/dL
  3. eAG (mmol/L) = 154.2 / 18.0 = 8.5667 -> 8.6 mmol/L (unrounded mg/dL divided by 18.0, which reproduces the published table)
  4. Published mmol/L line for comparison: 1.59 x 7 - 2.59 = 8.5 mmol/L
  5. IFCC = 10.93 x 7 - 23.50 = 53.01 -> 53 mmol/mol
  6. ADA range check on 7%: In the diabetes range (A1c >= 6.5%, >= 48 mmol/mol)

Results are general information, not financial, tax, legal, medical or engineering advice.