A1c reflects average blood sugar over the past two to three months, because glucose sticks to haemoglobin in red blood cells for their lifespan. Expressing it as an average glucose makes it easier to compare with finger-stick or sensor readings.
How to use the Estimated Average Glucose Calculator
- Hemoglobin A1c
- Every result field is editable: type into Estimated average glucose and Hemoglobin A1c plus every other field update to match.
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter your A1c percentage. The calculator applies the regression from the A1c-Derived Average Glucose study of 507 people, and also gives the IFCC units used in the UK and Europe.
A1c and average glucose
| A1c | IFCC | eAG mg/dL | eAG mmol/L |
|---|---|---|---|
| 5% | 31 | 97 | 5.4 |
| 5.7% | 39 | 117 | 6.5 |
| 6% | 42 | 125 | 7.0 |
| 6.5% | 48 | 140 | 7.7 |
| 7% | 53 | 154 | 8.5 |
| 7.5% | 58 | 169 | 9.3 |
| 8% | 64 | 183 | 10.1 |
| 9% | 75 | 212 | 11.7 |
| 10% | 86 | 240 | 13.3 |
| 11% | 97 | 269 | 14.9 |
| 12% | 108 | 298 | 16.5 |
What each result means
- Estimated average glucose = 28.7×[Hemoglobin A1c] – 46.7
- A1c in IFCC units = ([Hemoglobin A1c] – 2.15)×10.929
Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.
Formula
eAG (mg/dL) = 28.7 × A1c (%) − 46.7
eAG (mmol/L) = 1.59 × A1c (%) − 2.59
IFCC A1c (mmol/mol) = (A1c % − 2.15) × 10.929
Worked example
Inputs: Hemoglobin A1c: 7 %.
Results: Estimated average glucose = 154 mg/dL; A1c in IFCC units = 53 mmol/mol; A1c category (ADA) = Diabetes range.
Key terms
- HbA1c
- Glycated haemoglobin.
- eAG
- Estimated average glucose.
- IFCC
- International Federation of Clinical Chemistry units (mmol/mol).
Frequently asked questions
What A1c indicates diabetes?
6.5% or higher, confirmed by a repeat test.
What A1c should people with diabetes aim for?
Below 7% for many adults, individualised by your care team.
Why might A1c not match my meter?
Anaemia, recent blood loss, pregnancy, kidney disease and some haemoglobin variants affect A1c.