Not sure what your HbA1c result means? This free tool — built by a doctor — shows where your A1c sits (normal, prediabetes or diabetes range), works in either unit your report uses, estimates your average blood sugar, and gives you the questions to bring to your doctor. If you already have diabetes, one toggle re-reads it as how well controlled it is. It is educational only, and not a diagnosis.
HbA1c Interpreter
Enter your result to see where it sits — and what to ask your doctor.
Questions to ask your doctor
Want the full picture?
Get our free, doctor-written breakdowns of the tests that matter most — straight to your inbox.
Get the free guide → Read the full blood sugar guideThis tool is for general education and is not medical advice, a diagnosis, or a substitute for your doctor. Laboratory ranges and personal targets differ, so always read your result against your own lab’s range and discuss it with a qualified doctor.
© The Body Detectives · thebodydetectives.com
How to read your HbA1c
HbA1c (also written A1c) measures the share of your haemoglobin that has sugar attached to it, which reflects your average blood sugar over the past 2–3 months. It is reported either as a percentage (%) or in mmol/mol (1 IFCC unit). Using the American Diabetes Association thresholds, below 5.7% (39 mmol/mol) is normal, 5.7–6.4% (39–47 mmol/mol) is prediabetes, and 6.5% (48 mmol/mol) or above is the diabetes range. If you already live with diabetes, the number is read against a personal target — often under 7% (53 mmol/mol) — rather than for diagnosis. For the full story, read our guide to blood sugar levels.
Frequently asked questions
What is a normal HbA1c level?
Below 5.7% (39 mmol/mol) is considered normal. 5.7–6.4% (39–47 mmol/mol) is the prediabetes range, and 6.5% (48 mmol/mol) or higher is the diabetes range. A diagnosis is usually confirmed with a second test. Always read your result against your own lab’s reference range.
What does HbA1c actually measure?
It measures how much sugar has attached to the haemoglobin in your red blood cells. Because red cells live about three months, HbA1c reflects your average blood sugar over the past 2–3 months — not just the moment you were tested. That is why it is not affected by whether you fasted before the test.
What is a good HbA1c if I already have diabetes?
For many adults with diabetes, a common target is below 7% (53 mmol/mol), but targets are personal — some people are advised to aim tighter, and older adults or those prone to low-sugar episodes may be given a slightly higher target. Turn on the “already diagnosed” toggle in the tool to read your number against control targets, and confirm your own goal with your doctor.
% or mmol/mol — what’s the difference?
They are two units for the same test. The percentage is the older, everyday unit; mmol/mol is the newer IFCC unit used on many lab reports. For example, 6.5% is the same as 48 mmol/mol, and 7% is 53 mmol/mol. The tool above lets you enter either and shows the other.
Can I lower my HbA1c?
Often, yes. In the prediabetes range especially, changes to diet, weight and physical activity can bring the number down and sometimes return it to normal. If you have diabetes, your doctor may combine lifestyle changes with medication. Because HbA1c reflects three months, it is usually re-checked every few months to see the trend.
Can anything make HbA1c inaccurate?
Yes. Anaemia, haemoglobin conditions such as thalassaemia or sickle cell, recent blood loss or a transfusion, and pregnancy can all make HbA1c read falsely high or low. In these situations your doctor may rely on direct glucose tests instead. Gestational diabetes in particular is diagnosed with a glucose (OGTT) test, not HbA1c.
This tool and page are for general education only and are not medical advice, a diagnosis, or a substitute for your doctor. Prefer it on paper? Get our free Decode Your Labs guide.
