What Is a Normal A1c Level? Ranges Explained

What does the A1c test measure?

Hemoglobin A1c measures what percentage of hemoglobin — the oxygen-carrying protein in red blood cells — has glucose attached to it. Because red blood cells live for about three months, the A1c gives a weighted average of your blood sugar over that period, with the most recent weeks weighted most heavily 1Ref 1American Diabetes Association Professional Practice Committee (2024).2. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes-2024.A1c thresholds for normal (<5.7%), prediabetes (5.7–6.4%), and diabetes (≥6.5%); individualized A1c management targets; eAG conversion table; hemoglobin variant interference with A1c accuracy; prediabetes progression risk.

This makes A1c more informative than a single fasting glucose reading for understanding long-term blood sugar patterns. It is used both for diagnosis and for monitoring how well diabetes is being managed over time.

What do the different A1c ranges mean?

The American Diabetes Association defines the ranges as follows 1Ref 1American Diabetes Association Professional Practice Committee (2024).2. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes-2024.A1c thresholds for normal (<5.7%), prediabetes (5.7–6.4%), and diabetes (≥6.5%); individualized A1c management targets; eAG conversion table; hemoglobin variant interference with A1c accuracy; prediabetes progression risk:

| A1c | Category | |---|---| | Below 5.7% | Normal | | 5.7% – 6.4% | Prediabetes | | 6.5% or higher (confirmed on two tests) | Diabetes |

For people already diagnosed with type 2 diabetes, A1c is used to track management over time. A commonly used target is below 7%, though clinicians individualize this — a slightly higher target (such as 7.5–8%) may be appropriate for older adults, those with frequent hypoglycemia, or those with multiple health conditions and shorter life expectancy. A lower target may be appropriate for younger people with long life expectancy and no significant complications 1Ref 1American Diabetes Association Professional Practice Committee (2024).2. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes-2024.A1c thresholds for normal (<5.7%), prediabetes (5.7–6.4%), and diabetes (≥6.5%); individualized A1c management targets; eAG conversion table; hemoglobin variant interference with A1c accuracy; prediabetes progression risk.

For people with type 1 diabetes, targets are also individualized and typically monitored every 3 months.

What does prediabetes mean, and is it reversible?

Prediabetes means blood sugar is higher than normal but not yet at the diabetes threshold. Most people with prediabetes have no symptoms. Without intervention, a meaningful proportion — roughly one in three — will develop type 2 diabetes within five years 1Ref 1American Diabetes Association Professional Practice Committee (2024).2. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes-2024.A1c thresholds for normal (<5.7%), prediabetes (5.7–6.4%), and diabetes (≥6.5%); individualized A1c management targets; eAG conversion table; hemoglobin variant interference with A1c accuracy; prediabetes progression risk.

The landmark Diabetes Prevention Program trial demonstrated that structured lifestyle change — achieving roughly 7% body weight loss and at least 150 minutes of moderate physical activity per week — reduced the progression from prediabetes to type 2 diabetes by 58% over about 3 years 2Ref 2Knowler WC, Barrett-Connor E, Fowler SE, et al.; Diabetes Prevention Program Research Group (2002).Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin.Lifestyle intervention (7% weight loss + ≥150 min/week activity) reduced progression from prediabetes to type 2 diabetes by 58%; metformin by 31% over approximately 2.8 years in the landmark DPP trial. Metformin reduced progression by 31% in the same trial 2Ref 2Knowler WC, Barrett-Connor E, Fowler SE, et al.; Diabetes Prevention Program Research Group (2002).Reduction in the incidence of type 2 diabetes with lifestyle intervention or metformin.Lifestyle intervention (7% weight loss + ≥150 min/week activity) reduced progression from prediabetes to type 2 diabetes by 58%; metformin by 31% over approximately 2.8 years in the landmark DPP trial.

Prediabetes is not inevitable diabetes — it is a reversible warning sign. A Gale clinician can refer you to a recognized diabetes prevention program and help you create a practical plan.

What can affect A1c accuracy?

The A1c is reliable for most people but can be falsely altered in certain situations 1Ref 1American Diabetes Association Professional Practice Committee (2024).2. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes-2024.A1c thresholds for normal (<5.7%), prediabetes (5.7–6.4%), and diabetes (≥6.5%); individualized A1c management targets; eAG conversion table; hemoglobin variant interference with A1c accuracy; prediabetes progression risk3Ref 3American Diabetes Association Professional Practice Committee (2025).2. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes-2025.Updated guidance on A1c accuracy limitations including hemoglobin variants and red blood cell disorders; recommendation for alternative diagnostic tests when A1c may be unreliable:

• Hemoglobin variants — sickle cell trait, sickle cell disease, or other hemoglobin variants can cause falsely low or high readings depending on the laboratory method used; these variants are more common in people of African, Mediterranean, and Southeast Asian ancestry
• Hemolytic anemia or iron-deficiency anemia — conditions that affect red blood cell lifespan can shift A1c readings by changing the denominator of the calculation
• Kidney disease or liver disease — can affect red blood cell turnover and alter results
• Recent blood transfusion — replaces circulating red blood cells and changes the baseline

If any of these apply, your clinician may rely on fasting glucose or a glucose tolerance test rather than A1c alone, or may specify a laboratory method that accounts for hemoglobin variants.

Does A1c correspond to specific blood sugar readings?

Yes. There is an estimated average glucose (eAG) that corresponds to each A1c value, which can help translate the lab number into terms familiar from home blood sugar monitoring 1Ref 1American Diabetes Association Professional Practice Committee (2024).2. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes-2024.A1c thresholds for normal (<5.7%), prediabetes (5.7–6.4%), and diabetes (≥6.5%); individualized A1c management targets; eAG conversion table; hemoglobin variant interference with A1c accuracy; prediabetes progression risk:

| A1c | Estimated Average Glucose | |---|---| | 5.7% | ~117 mg/dL | | 6.0% | ~126 mg/dL | | 6.5% | ~140 mg/dL | | 7.0% | ~154 mg/dL | | 8.0% | ~183 mg/dL | | 9.0% | ~212 mg/dL |

These are population-level averages — individual relationships between A1c and daily blood sugar vary, particularly in people with hemoglobin variants or altered red blood cell turnover 1Ref 1American Diabetes Association Professional Practice Committee (2024).2. Diagnosis and Classification of Diabetes: Standards of Care in Diabetes-2024.A1c thresholds for normal (<5.7%), prediabetes (5.7–6.4%), and diabetes (≥6.5%); individualized A1c management targets; eAG conversion table; hemoglobin variant interference with A1c accuracy; prediabetes progression risk.