Tools & Resources

HbA1c Calculator

Your HbA1c (also known as A1c or glycated hemoglobin) can provide a general gauge of your diabetes management, as it reflects an average blood glucose level over the past few months.

Learn more about HbA1c and use our calculator to estimate your HbA1c here.

*The eHbA1c (estimated HbA1c) calculated here is just an estimation based on the average blood glucose you have entered. It should not replace the HbA1c check carried out by your doctor, and the result shown here may differ from the lab value you get. This calculation should not be used to make therapy decisions or changes. You can discuss with your healthcare professional how this approximate measurement could help you in your overall diabetes management.

What is HbA1c?

You should have your HbA1c level checked by your healthcare professional at least once a year, and possibly more frequently, depending on your diabetes management needs. The HbA1c test measures your average blood glucose levels by taking a blood sample. This is then sent to a lab for analysis of the results.

Here's how it works:

Sugar (or glucose) naturally attaches itself to cells as they move through your bloodstream. When this happens, the cell is considered "glycated”. Everyone (whether they have diabetes or not) has glycated blood cells. The more sugar you have in your blood, the more that sticks to the cells. These are permanent, however, as red blood cells only last for approximately 4 months, new ones are continually being produced. That is why your HbA1c can only give an average of blood glucose over the last 2-3 months.

The more glucose in your blood, the higher the percentage of glycated red blood cells you'll have, and the higher your HbA1c result will be.

How is HbA1c measured?

Unlike blood glucose readings using a finger-prick test, which are reported as mmol/L, HbA1c is reported as a percentage (%) or in mmol/mol. For example, if you check blood glucose 100 times in a month, and your average result is 10.5 mmol/l, this would lead to an HbA1c of approximately 66 mmol/mol (8.2%), which is above the recommended American Diabetes Association (ADA) targets.

What should be my target HbA1c?

You should determine the right target level for you, together with your Healthcare Professional. This will depend on your type of diabetes therapy, the duration of your diabetes, and any previous HbA1c results.

According to the American Diabetes Association the HbA1c target for most non-pregnant adults is <7%.¹

HbA1c calculator

The calculation below is provided to illustrate the relationship between HbA1c and average blood glucose levels. This calculation is not meant to replace an actual lab HbA1c result, but to help you better understand the relationship between your test results and your HbA1c. Use this information to become more familiar with the relationship between average blood glucose levels and HbA1c.

The importance of self-monitoring blood glucose and HbA1c

HbA1c is important, but it's not a substitute for structured self-monitoring. Only regular blood glucose checks show you how meals, activity, medications, and stress affect your blood glucose at a single moment in time, as well as over the course of a day or week.

Without regular self-checking to provide day-to-day insights, an HbA1c result can be confusing. Because it gives an average view, a person with frequent highs and lows could have an in-range result that is the same as someone with blood glucose consistently in the target range.

This is why self-monitoring blood glucose levels is valuable. Remember, one blood glucose check in isolation will not tell you the whole story. Getting the results is one thing, but knowing what to do with them is key. Making the most of your data can help you to make better decisions about your health, such as dietary choices and insulin doses.

The only way to get a complete picture of your blood glucose is by reviewing your day-to-day self-checks along with your regular HbA1c tests, and working closely with your Healthcare Professional to interpret the results. Find out more about blood glucose monitoring here.

Sources:

1. The A1C Test & Diabetes [Internet]. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). 2018 Apr [cited 2025 Jul 10]. Available from: https://www.niddk.nih.gov/health-information/diagnostic-tests/a1c-test
2. American Diabetes Association Professional Practice Committee. Standards of Care. Diabetes Care. 2025;48(1):S1-S352.

The calculation below is provided to illustrate the relationship between HbA1c and average blood glucose levels. This calculation is not meant to replace an actual lab HbA1c result, but to help you better understand the relationship between your test results and your HbA1c. Use this information to become more familiar with the relationship between average blood glucose levels and HbA1c.