The calculation runs in your browser; no data is sent or stored. The result is for information only and does not replace assessment by your doctor.
What is HbA1c (glycated haemoglobin)?
HbA1c, or glycated haemoglobin, shows how much glucose has attached to the haemoglobin in your red blood cells over roughly the past 2–3 months. HbA1c reflects your average blood glucose over this period rather than the value at a single moment, because red blood cells live for about three months on average. It is the main indicator used to track long-term diabetes control.
How is HbA1c converted to estimated average glucose (eAG)?
Estimated average glucose (eAG) translates HbA1c into a value expressed in the same units as your everyday blood glucose. The formula used internationally is: eAG in mg/dL equals 28.7 multiplied by HbA1c in %, minus 46.7. For example, an HbA1c of 7% corresponds to an average blood glucose of about 154 mg/dL, or 8.6 mmol/L. The calculator above performs this conversion automatically, in both units.
What is the IFCC value (mmol/mol) and how does it relate to percentages?
In addition to the percentages traditionally used (the DCCT/NGSP system), HbA1c can also be expressed in mmol/mol, according to the international IFCC standard. The two convert into one another: mmol/mol equals HbA1c in percent minus 2.15, all multiplied by 10.929. For example, 7% corresponds to 53 mmol/mol, and 6.5% to 48 mmol/mol. Many lab reports now show both values.
What HbA1c target should I aim for?
For many adults with diabetes, a common target is an HbA1c below 7%, but the right value for you is set individually, together with your doctor. It may be stricter in younger people or more relaxed in older adults or those at risk of hypoglycaemia. The calculator shows which average blood glucose your value corresponds to, but it does not replace a conversation with your medical team.