HbA1c Converter (to mg/dL & mmol/L)
This free HbA1c converter turns your HbA1c percentage into estimated average glucose (eAG) — in both mg/dL and mmol/L — and back again, using the standard ADAG formula your lab uses.
- ADAG / ADA formula
- Instant, two-way
- Private — nothing stored
An HbA1c of 7.0% is in the diabetes range, and is the common target ceiling for many adults with diabetes.
HbA1c to glucose chart
| HbA1c (%) | eAG (mg/dL) | eAG (mmol/L) | Category |
|---|---|---|---|
| 5.0 | 97 | 5.4 | Normal |
| 5.7 | 117 | 6.5 | Prediabetes |
| 6.5 | 140 | 7.8 | Diabetes |
| 7.0 | 154 | 8.6 | Diabetes |
| 8.0 | 183 | 10.2 | Diabetes |
| 9.0 | 212 | 11.8 | Diabetes |
| 10.0 | 240 | 13.4 | Diabetes |
This tool gives a population-average estimate, not a diagnosis. Individual results vary, and conditions like anaemia or pregnancy can affect accuracy. Always discuss your HbA1c with a doctor. Categories follow ADA cut-offs (Normal <5.7%, Prediabetes 5.7–6.4%, Diabetes ≥6.5%).
Using the HbA1c converter
HbA1c shows your average blood sugar over the past 2–3 months as a percentage. The converter turns that percentage into the everyday glucose numbers (mg/dL or mmol/L) you see on a home glucometer.
Enter your value
Type your HbA1c percentage from your lab report — or switch direction to enter an average glucose reading instead.
See it both ways
Get the estimated average glucose instantly in both mg/dL and mmol/L, so it matches whatever your meter shows.
Read your range
The tool shows whether your value falls in the normal, prediabetes or diabetes range, with what it means.
What does your HbA1c level mean?
These are the standard ADA cut-offs used worldwide. Your doctor reads your HbA1c alongside your symptoms, other tests and overall health before making any diagnosis.
Your average blood sugar is in the healthy, non-diabetic range. Roughly under 117 mg/dL average glucose.
- Keep up balanced eating and activity
- Recheck if you have risk factors
Blood sugar is higher than normal but not yet diabetes. This stage can often be reversed with lifestyle changes.
- Improve diet, activity and weight now
- Repeat the test as your doctor advises
An HbA1c of 6.5% or higher, usually on two tests, indicates diabetes. Most adults aim for a target below 7%.
- See a doctor to confirm and plan care
- Track HbA1c every 3–6 months
Want the full picture on testing? See how diabetes is diagnosed, or check your overall risk with our diabetes risk calculator.
Why HbA1c matters — and how it differs from a finger-prick
A single glucometer reading shows your sugar at one moment. HbA1c shows the bigger picture — your average over months — which is why doctors rely on it to diagnose and track diabetes.
What HbA1c measures
HbA1c is the percentage of your haemoglobin (in red blood cells) that has glucose stuck to it. The more sugar in your blood over time, the higher the percentage.
A 2–3 month average
Because red blood cells live about 3 months, HbA1c reflects your average blood sugar over that period — not just today. One bad or good day barely moves it.
Why it beats one reading
A finger-prick swings with meals, stress and time of day. HbA1c smooths out those ups and downs, giving a stable measure of your overall control.
When it's less reliable
Conditions that change red blood cells — anaemia, pregnancy, recent blood loss or some haemoglobin variants — can make HbA1c less accurate. Your doctor will allow for this.
- Sugar at a single moment
- Changes with food, stress, time
- Good for daily self-monitoring
- Average over 2–3 months
- Not affected by one meal or day
- Used to diagnose & track diabetes
Both tests work together: HbA1c for the long-term trend, finger-pricks for day-to-day decisions. Use the HbA1c converter above to turn your percentage into everyday glucose numbers, or learn more in our complete guide to diabetes.
HbA1c converter FAQs
What is the formula to convert HbA1c to average glucose?
The standard ADAG formula is: estimated average glucose (mg/dL) = 28.7 × HbA1c − 46.7. For mmol/L, divide the mg/dL value by 18. So an HbA1c of 7% ≈ 154 mg/dL or 8.6 mmol/L.
What is a normal HbA1c level?
By ADA cut-offs: below 5.7% is normal, 5.7–6.4% is prediabetes, and 6.5%+ is diabetes. Most adults with diabetes aim for below 7%, but your doctor sets your personal target.
Is the HbA1c to glucose conversion exact?
No — it's a population-average estimate. Two people with the same HbA1c can have slightly different average glucose. Use it as a guide; your doctor interprets your actual results.
Can HbA1c be wrong or unreliable?
It can be less accurate with anaemia, recent blood loss, pregnancy, kidney disease or certain haemoglobin variants. In those cases a doctor may rely more on direct glucose tests.
How often should HbA1c be tested?
Often about every 6 months if well-controlled, or every 3 months if treatment changed or control is poor. Your doctor decides the right frequency for you.
Does this replace a lab test?
No. This converter only translates between HbA1c and average glucose. You still need an actual lab HbA1c test, ordered and interpreted by a doctor, for diagnosis and monitoring.
Sources & references
- Nathan DM, et al. Translating the A1C Assay Into Estimated Average Glucose Values (ADAG Study). Diabetes Care, 2008.
- American Diabetes Association. Standards of Care in Diabetes — Diagnosis & A1C. ADA, 2024. diabetes.org
- National Institute of Diabetes and Digestive and Kidney Diseases. The A1C Test & Diabetes. NIDDK / NIH, 2024. niddk.nih.gov
Replace or expand with the exact citations and access dates used at publish time.
This converter and its content are for informational and educational purposes only, and are not a substitute for professional medical advice, diagnosis, or treatment. Results are estimates, not a diagnosis. Always discuss your HbA1c and blood sugar with a qualified doctor. Read our full Medical Disclaimer.