Lab units · HbA1c
A1c to average glucose, eAG and mmol/mol.
Convert an A1c percentage to estimated average glucose (eAG) and to the IFCC mmol/mol unit, or work backwards from an average glucose or an IFCC value.
Convert an A1c
Result
Enter an A1c percentage, an IFCC value or an average glucose.
The two equations
ADAG (estimated average glucose): eAG in mg/dL = 28.7 × A1c − 46.7. In mmol/L: eAG = 1.59 × A1c − 2.59. This comes from the A1c-Derived Average Glucose (ADAG) study, which compared A1c with continuous and frequent glucose measurements over about three months. It is an estimate: an individual's measured average can differ from the equation.
IFCC (mmol/mol): IFCC value = 10.929 × (NGSP % − 2.15). Going back, NGSP % = 0.09148 × IFCC + 2.152. Countries such as the UK and Australia report A1c in mmol/mol; the US reports percent; Canada reports percent and often mmol/mol together.
Worked example
An A1c of 7.0% gives eAG = 28.7 × 7.0 − 46.7 = 154 mg/dL (8.5 mmol/L), and an IFCC value of 10.929 × (7.0 − 2.15) = 53 mmol/mol.
A1c conversion chart
| A1c (NGSP) | A1c (IFCC) | eAG (mg/dL) | eAG (mmol/L) |
|---|---|---|---|
| 5.0% | 31 mmol/mol | 97 mg/dL | 5.4 mmol/L |
| 5.5% | 37 mmol/mol | 111 mg/dL | 6.2 mmol/L |
| 6.0% | 42 mmol/mol | 126 mg/dL | 7.0 mmol/L |
| 6.5% | 48 mmol/mol | 140 mg/dL | 7.7 mmol/L |
| 7.0% | 53 mmol/mol | 154 mg/dL | 8.5 mmol/L |
| 7.5% | 58 mmol/mol | 169 mg/dL | 9.3 mmol/L |
| 8.0% | 64 mmol/mol | 183 mg/dL | 10.1 mmol/L |
| 8.5% | 69 mmol/mol | 197 mg/dL | 10.9 mmol/L |
| 9.0% | 75 mmol/mol | 212 mg/dL | 11.7 mmol/L |
| 10.0% | 86 mmol/mol | 240 mg/dL | 13.3 mmol/L |
| 11.0% | 97 mmol/mol | 269 mg/dL | 14.9 mmol/L |
| 12.0% | 108 mmol/mol | 298 mg/dL | 16.5 mmol/L |
Limits
The ADAG relationship was derived from a study population and does not apply equally to everyone. Conditions that change red-cell lifespan, such as anaemia, haemoglobin variants, recent transfusion or pregnancy, can make A1c and average glucose diverge. The equation is meant for reading a reported A1c in glucose terms, not for setting targets.
Sources
Nathan DM et al., Translating the A1C assay into estimated average glucose values, Diabetes Care 2008;31:1473-1478. NGSP/IFCC master equation from the National Glycohemoglobin Standardization Program (ngsp.org) and the IFCC standardisation committee.
Frequently asked questions
What is eAG?
eAG is estimated average glucose: the average blood glucose that a given A1c corresponds to in the ADAG study. It lets an A1c percentage be read in the same units as a glucose meter.
How do I convert A1c to average glucose?
Multiply the A1c percentage by 28.7 and subtract 46.7 to get mg/dL. For 6.0% that is 28.7 × 6.0 − 46.7 = 125.5, shown as 126 mg/dL on the published ADAG table.
How do I convert A1c percent to mmol/mol?
Subtract 2.15 from the percentage and multiply by 10.929. For 7.0% that is 53 mmol/mol.
Does this tell me if I have diabetes?
No. This page converts units and applies a published equation. Diagnosis and targets are decided by a clinician using the right tests for your situation.
Reference information, not medical advice
This page converts units only. It does not interpret a result, and units and reference intervals differ between laboratories. Ask the clinician who ordered the test or the reporting laboratory what a result means for you. If you are worried about a result or symptoms, contact a health professional; in an emergency call your local emergency number.