HbA1c Calculator

HbA1c (glycated haemoglobin or haemoglobin A1c) is a blood test that reflects your average blood glucose level over the past 2-3 months. Glucose in the bloodstream attaches to haemoglobin in red blood cells; the higher and more prolonged the blood glucose, the more haemoglobin becomes glycated. Because red blood cells live for about 90 days, HbA1c provides a longer-term picture than a single fasting glucose test.

An HbA1c below 5.7% (39 mmol/mol) is considered normal. A level of 5.7-6.4% (39-46 mmol/mol) indicates prediabetes, and 6.5% (48 mmol/mol) or above on two separate tests is diagnostic of type 2 diabetes according to the American Diabetes Association. The WHO uses a threshold of 6.5% (48 mmol/mol) as well.

For most adults with type 2 diabetes, the American Diabetes Association recommends an HbA1c target of below 7% (53 mmol/mol). A target of below 6.5% may be appropriate for younger patients with short disease duration and no significant cardiovascular disease. Less stringent targets of below 8% (64 mmol/mol) are acceptable for older adults with complex medical conditions or a history of severe hypoglycaemia. Targets should always be individualised with your healthcare provider.