This HbA1c converter switches your long-term blood sugar value between percent (%) and mmol/mol and estimates your average blood glucose over the past weeks. Enter either value.
Why are there two units?
HbA1c shows how much of the red blood pigment haemoglobin has glucose attached. For a long time it was reported in percent. Since international standardisation by the IFCC it has also been reported in mmol/mol, and many laboratories give both. The conversion uses the official equation: % = 0.09148 × mmol/mol + 2.152.
Reference values
- below 5.7 % (below 39 mmol/mol): normal range
- 5.7 to 6.4 % (39 to 47 mmol/mol): raised, a sign of prediabetes
- 6.5 % or more (48 mmol/mol or more): diabetes range – the diagnosis is made by a doctor, usually after a confirming test
What is estimated average glucose?
HbA1c can be used to estimate average blood glucose over roughly the last eight to twelve weeks, based on the international ADAG study. The value is an approximation: anaemia, kidney disease, pregnancy or certain haemoglobin variants can distort HbA1c.
Frequently asked questions
What HbA1c target applies in diabetes?
The treatment target is set individually, depending on age, other conditions and the risk of low blood sugar. Discuss your target with your doctor.
Do I need to fast for an HbA1c test?
No. HbA1c reflects the past weeks and hardly depends on your last meal.
How often is HbA1c measured?
In known diabetes usually every three to six months, depending on treatment and progress.
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Note: This calculator provides general information and does not replace medical advice, diagnosis or treatment. Your entries are not stored.