HbA1c mmol/mol to % Calculator and Conversion Chart
HbA1c mmol/mol to % Calculator and Conversion Chart
Convert HbA1c results from mmol/mol to percentage (%) instantly, or enter a percentage to see its IFCC mmol/mol equivalent.
Common UK laboratory unit.
Older DCCT / NGSP reporting format.
Quick HbA1c conversion chart
Looking for the answer to “what is HbA1c 42 mmol/mol in percent?” 42 mmol/mol is approximately 6.0%. Use the table below for commonly searched HbA1c values.
| HbA1c (mmol/mol) | HbA1c (%) |
|---|---|
| 31 | 5.0% |
| 37 | 5.5% |
| 42 | 6.0% |
| 48 | 6.5% |
| 53 | 7.0% |
| 58 | 7.5% |
| 64 | 8.0% |
| 75 | 9.0% |
| 86 | 10.0% |
| 97 | 11.0% |
| 108 | 12.0% |
How to use this HbA1c calculator
- Find your HbA1c figure on your blood-test result or clinic letter.
- Check whether it is reported as mmol/mol (the usual UK format) or as a percentage.
- Type the number into the matching box above. The other unit updates automatically.
- Use the result to understand a report written in another format—not to change medication or treatment on its own.
For example, entering 42 mmol/mol gives 6.0%. Entering 7.0% gives approximately 53 mmol/mol.
What is HbA1c?
HbA1c, also called glycated haemoglobin, is a blood test that reflects average glucose exposure over roughly the previous two to three months. Glucose in the bloodstream attaches to haemoglobin in red blood cells. Because red blood cells circulate for weeks, HbA1c provides a longer-term picture than a single finger-prick or fasting glucose result.
In the UK, HbA1c is usually reported in mmol/mol, following the IFCC standard. You may still see HbA1c written as a percentage in older information, international articles, diabetes apps or results from some overseas laboratories. They describe the same measurement, simply on different scales.
HbA1c mmol/mol vs percentage: why are there two units?
The percentage format is commonly called the DCCT or NGSP unit. The mmol/mol format is the IFCC unit and is standard in UK clinical practice. Neither format is more “accurate”; the numbers look different because the scales are different.
The conversion used by this calculator is:
- HbA1c (%) = (HbA1c mmol/mol × 0.09148) + 2.152
- HbA1c (mmol/mol) = (HbA1c % − 2.152) ÷ 0.09148
Results are rounded to one decimal place, which is appropriate for a simple conversion display.
What HbA1c number means diabetes?
In UK practice, HbA1c may be used as one of the tests to help diagnose type 2 diabetes. A result of 48 mmol/mol (6.5%) or above is a diagnostic threshold used in the right clinical setting. A healthcare professional considers the result alongside symptoms, repeat testing where needed, medical history and factors that can affect HbA1c accuracy.
Do not try to self-diagnose from a conversion chart. HbA1c is not appropriate for every situation—for example, some blood disorders, recent blood loss or transfusion, pregnancy, and conditions that alter red-cell lifespan can make the figure less reliable. Your clinician may instead use plasma glucose testing.
Why might my HbA1c target differ from someone else’s?
For people living with diabetes, an HbA1c target is individual. It can depend on the type of diabetes, treatment, risk of hypoglycaemia, age, pregnancy, other health conditions and what is realistic and safe for that person. Your diabetes team can explain the target on your own record and the balance between glucose management, daily life and avoiding hypos.
Frequently asked questions
What is 42 mmol/mol HbA1c in percent?
42 mmol/mol converts to approximately 6.0%.
What is 48 mmol/mol HbA1c in percent?
48 mmol/mol converts to approximately 6.5%.
What is 53 mmol/mol HbA1c in percent?
53 mmol/mol converts to approximately 7.0%.
Is HbA1c measured in mmol/L?
No. HbA1c is normally reported as mmol/mol or as a percentage. Blood glucose is a different measurement and is often reported as mmol/L in the UK.
Can I convert HbA1c into an average blood glucose?
There are estimated-average-glucose formulae, but they are not a substitute for glucose monitoring and may not match an individual’s readings exactly. Ask your diabetes team which measurements are most useful for you.
Why does my HbA1c not match my finger-prick readings?
HbA1c is a longer-term average and does not show day-to-day highs and lows. Meter technique, timing, medication, illness and conditions affecting red blood cells can all affect how results compare.
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