Health Tools

HbA1c Calculator

Turn an HbA1c result into the average blood sugar it represents, in mg/dL and mmol/L — or estimate HbA1c from your average glucose — with the diabetes ranges alongside.

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The tool

Convert HbA1c and average glucose

Your HbA1c result is on your lab report, as a percentage or in mmol/mol.
I want to convert
HbA1c unit
Reference

HbA1c ranges and average glucose

American Diabetes Association diagnostic ranges, with the average glucose each HbA1c level reflects over the past 2–3 months.
HbA1cmmol/molAverage glucoseRange
5.0% 31 97 mg/dL · 5.4 mmol/L Normal
5.7% 39 117 mg/dL · 6.5 mmol/L Prediabetes starts
6.5% 48 140 mg/dL · 7.8 mmol/L Diabetes range starts
7.0% 53 154 mg/dL · 8.6 mmol/L Diabetes range
8.0% 64 183 mg/dL · 10.2 mmol/L Diabetes range
9.0% 75 212 mg/dL · 11.8 mmol/L Diabetes range
10.0% 86 240 mg/dL · 13.4 mmol/L Diabetes range
Method

How it is calculated

The exact formulas this calculator uses, and where they come from.
Average glucose eAG (mg/dL) = 28.7 × HbA1c (%) − 46.7
In mmol/L eAG (mg/dL) ÷ 18
IFCC units HbA1c (mmol/mol) = (HbA1c % − 2.15) × 10.929
Reverse HbA1c (%) = (eAG mg/dL + 46.7) ÷ 28.7

The average-glucose equation comes from the A1c-Derived Average Glucose (ADAG) study and is the one the American Diabetes Association uses.

Ranges: under 5.7% normal, 5.7–6.4% prediabetes, 6.5% or more in the diabetes range. A diagnosis needs confirmation by a doctor, usually with a repeat test.

For general information only — not medical advice, diagnosis or treatment. These calculators use population formulas that cannot account for every individual, and are meant for adults unless stated. Always speak to a qualified doctor about your health, and never delay seeking care because of a result here.