HbA1c (also written A1C) is your blood sugar report card for the last three months.
It does not measure today's sugar level. It measures how much sugar has stuck to your red blood cells over their lifespan — about 90 days. Higher average sugar → higher HbA1c.
The ranges that matter
- Below 5.7% — Normal. Your blood sugar has been in healthy range.
- 5.7% to 6.4% — Prediabetes. A warning that needs action now, not later.
- 6.5% or higher — Diabetes. Two tests in this range = diagnosis.
- For people already diagnosed — goal is usually under 7%, individualised by your doctor based on age, other conditions, and life situation.
Translating to average blood sugar
Each 1% of HbA1c roughly corresponds to a 28-29 mg/dL change in average blood sugar.
- HbA1c 6% ≈ average sugar 126 mg/dL
- HbA1c 7% ≈ average sugar 154 mg/dL
- HbA1c 8% ≈ average sugar 183 mg/dL
- HbA1c 9% ≈ average sugar 212 mg/dL
- HbA1c 10% ≈ average sugar 240 mg/dL
What HbA1c does not tell you
It does not show variability. Two people with HbA1c 7% can have very different lives — one is steady at 154, the other swings from 60 to 250 every day. The second is much more dangerous. That is why your doctor may also want to see a CGM trace or a logbook.
Confused about your latest report? Drop it in DiaCare AI — it can explain the numbers in plain language, but never as a replacement for your doctor.