🩺 Diabetes
HbA1c Levels Chart — What Your Result Means (2026)
Complete HbA1c levels chart for UK (mmol/mol) and USA (%). What each range means, target levels for diabetics, and how to lower your HbA1c. Updated January 2026.
Key Takeaways
- HbA1c measures average blood glucose over 2–3 months — not a snapshot
- Normal HbA1c is below 42 mmol/mol (6.0%) in the UK
- Prediabetes range: 42–47 mmol/mol (6.0–6.4%)
- Type 2 diabetes is diagnosed at 48 mmol/mol (6.5%) or above
- Each 1% (11 mmol/mol) reduction in HbA1c reduces diabetes complications by 35%
What Is HbA1c?
HbA1c (glycated haemoglobin) measures the percentage of haemoglobin molecules in your red blood cells that have glucose attached to them. Because red blood cells live for approximately 3 months, HbA1c reflects average blood glucose over that period — providing a much more comprehensive picture than a single glucose reading.
2–3 months
Period that HbA1c reflects blood glucose control
35%
Reduction in complications per 1% HbA1c reduction
48 mmol/mol
Threshold for Type 2 diabetes diagnosis (UK)
HbA1c Reference Chart — UK and USA
| Category | UK (mmol/mol) | USA (%) | Clinical Action |
|---|---|---|---|
| Normal / Non-diabetic | Below 42 | Below 6.0% | Routine screening as advised |
| Prediabetes | 42–47 | 6.0–6.4% | Lifestyle intervention urgently; annual review |
| Type 2 Diabetes Diagnosis | 48 or above | 6.5% or above | Confirm with repeat test; treatment discussion |
| T2D — Well Controlled | 48–58 | 6.5–7.5% | Continue current management; review annually |
| T2D — Moderate Control | 59–74 | 7.5–9.0% | Medication review; lifestyle intensification |
| T2D — Poor Control | 75 or above | 9.0% or above | Urgent medication review; specialist referral |
Target HbA1c for People with Diabetes
Standard NICE Target (UK)
- On diet/lifestyle only or metformin: 48 mmol/mol (6.5%)
- On medication with hypoglycaemia risk: 53 mmol/mol (7.0%)
- Elderly or frail patients: Individual — often relaxed to 58–64 mmol/mol
Individualised Targets
The key insight: tighter HbA1c targets reduce long-term complications but increase hypoglycaemia risk. For young patients with newly diagnosed diabetes, targeting 48 mmol/mol reduces lifetime complication risk dramatically. For elderly patients with established complications, a target of 64 mmol/mol may be more appropriate — avoiding the risks of tight control (hypoglycaemia, falls, cardiac events in those with CVD).
How to Lower HbA1c
| Intervention | Expected HbA1c Reduction | Timeframe |
|---|---|---|
| Low-carbohydrate diet | 0.9–1.5% | 3–6 months |
| Weight loss (10% body weight) | 0.5–1.5% | 3–6 months |
| Exercise (150 min/week) | 0.3–0.6% | 3 months |
| Metformin 2,000mg | 1.0–1.5% | 3 months |
| GLP-1 agonist (semaglutide) | 1.5–1.8% | 3–6 months |
| Tirzepatide (Mounjaro) | 2.1–2.3% | 3–6 months |
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What is a normal HbA1c level?▼
Normal (non-diabetic): below 42 mmol/mol (UK) / below 6.0% (USA). Prediabetes: 42–47 mmol/mol / 6.0–6.4%. Diabetes diagnosis: 48+ mmol/mol / 6.5%+. Note: a single elevated HbA1c requires confirmation with a repeat test (unless very high or symptomatic) before a diabetes diagnosis is made.
How quickly can I lower my HbA1c?▼
HbA1c reflects the past 2–3 months, so it takes at least 3 months to see meaningful changes. With a low-carbohydrate diet + weight loss, some people reduce HbA1c by 1.5–2% within 3 months. With GLP-1 medications, maximum HbA1c reduction typically takes 3–6 months (at therapeutic dose). Most tests are done every 3 months in people with poorly controlled diabetes.
Can HbA1c be high without diabetes?▼
Yes — HbA1c can be falsely elevated or affected by various conditions: iron deficiency anaemia, vitamin B12 deficiency, haemolytic anaemia (falsely low), certain haemoglobin variants (HbS in sickle cell, HbC), splenomegaly, and recent blood transfusion. If HbA1c result doesn't match symptoms or fasting glucose, discuss alternative testing methods with your GP.
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⚕️ Medical Disclaimer: For informational purposes only. Always consult a qualified healthcare professional before starting or changing any medication or treatment.
Dr
Dr. Priya Sharma, MD
WellCalc Medical Contributor
All articles reviewed by qualified healthcare professionals following NHS, AHA, and WHO guidelines.