HbA1c shows your average blood glucose over roughly the past 2–3 months. Below 5.7% is normal, 5.7–6.4% is prediabetes and 6.5% or higher suggests diabetes. An HbA1c of 7% matches an average glucose of about 154 mg/dL. It's the standard blood test for spotting and tracking diabetes.
Last updated: November 2026
The problem
Your lab report says "HbA1c: 6.1%". Your doctor says "borderline". You nod, but what does that number actually mean, and how is it different from the fasting sugar you checked last week?
It's worth knowing. A national ICMR-INDIAB survey found 15.3% of Indian adults have prediabetes, many without realising it (Anjana et al., 2023).
Why it happens
HbA1c (glycated haemoglobin) is the share of haemoglobin in your red blood cells that has glucose stuck to it. The more glucose in your blood over time, the more sticks. Red blood cells live for about three months, so HbA1c reflects your average over roughly that period.
That makes it different from a fasting glucose test, which is a snapshot of one moment.
What the numbers mean
The American Diabetes Association uses these HbA1c ranges (ADA, 2025):
| HbA1c | What it suggests | Estimated average glucose |
|---|---|---|
| Below 5.7% | Normal | Below about 117 mg/dL |
| 5.7–6.4% | Prediabetes | About 117–137 mg/dL |
| 6.5% or higher | Diabetes (confirmed with a repeat test) | About 140 mg/dL or higher |
| 7% | A common treatment target for many adults with diabetes | About 154 mg/dL |
The average glucose figures come from a large study that linked HbA1c to continuous glucose readings: estimated average glucose = 28.7 × HbA1c − 46.7 (Nathan et al., 2008).
HbA1c can be misleading in some situations, such as anaemia, some haemoglobin variants or pregnancy. Your doctor may use other tests then (ADA, 2025).
What to do
- Know your number. The ADA advises testing all adults from age 35, and earlier if you have risk factors such as extra weight or a family history of diabetes (ADA, 2025).
- Retest at the interval your doctor suggests. Because HbA1c reflects about 3 months, testing more often than that usually won't show much change.
- Look at the trend, not one result. A move from 6.2% to 5.9% is meaningful progress.
- Work on the daily spikes. Walking after meals, eating carbs last and choosing lower-GI foods all help. Start with our guide to walking after meals.
Did you know? Each 1% rise in HbA1c adds roughly 29 mg/dL to your estimated average glucose. 6% is about 126 mg/dL; 8% is about 183 mg/dL (Nathan et al., 2008).
FAQ
What is a normal HbA1c level?
Below 5.7% is considered normal. 5.7–6.4% is prediabetes, and 6.5% or above suggests diabetes, usually confirmed with a second test.
Is HbA1c 6.0% prediabetes?
Yes. 6.0% falls in the 5.7–6.4% prediabetes range. It's a good moment to talk to your doctor about diet, activity and follow-up testing.
Do I need to fast for an HbA1c test?
No. HbA1c reflects your average over about 3 months, so fasting isn't needed. Your doctor may still order a fasting glucose test alongside it.
How is HbA1c different from fasting sugar?
Fasting glucose is a single moment. HbA1c is an average over about 3 months, so it gives a bigger picture.
Want to go deeper? Read the science behind steady glucose.
This article is for information, not medical advice. If you have diabetes or take medication, talk to your doctor before changing your diet.
References
- American Diabetes Association Professional Practice Committee. 2. Diagnosis and classification of diabetes: Standards of Care in Diabetes—2025. Diabetes Care, 2025.
- Nathan DM, et al. Translating the A1C assay into estimated average glucose values. Diabetes Care, 2008.
- Anjana RM, et al. Metabolic non-communicable disease health report of India: the ICMR-INDIAB national cross-sectional study (ICMR-INDIAB-17). Lancet Diabetes & Endocrinology, 2023.
