First principles
What an A1C level actually measures
A1C, also called HbA1c or glycated hemoglobin, measures the proportion of hemoglobin with glucose attached. Because hemoglobin is carried in red blood cells that circulate for weeks, the test offers a longer view of glucose exposure than a finger-stick taken at one moment. It does not require fasting and is used both to screen for type 2 diabetes and to monitor people already diagnosed with diabetes.
The result is weighted by biology, not divided evenly across a calendar quarter. More recent glucose exposure can influence A1C more strongly than earlier weeks. A value therefore should not be interpreted as a simple average of exactly 90 days. It also cannot show whether glucose is stable or swinging between highs and lows.
US reports usually express A1C as a percentage. Many international reports use IFCC mmol/mol. These units describe the same laboratory measurement, while mmol/L describes glucose concentration. Use our A1C unit converter when comparing records from different systems.
Screening category and treatment goal are different questions
The three ranges at the top answer a diagnostic question for someone being screened: is the result below the prediabetes threshold, within the prediabetes range, or at the diabetes threshold? Once diabetes has been diagnosed, care shifts toward a treatment goal. A person with a treated A1C below 6.5% has not necessarily stopped having diabetes; the result may indicate that management is working.
According to the American Diabetes Association’s 2026 Standards of Care, an A1C goal below 7% is appropriate for many nonpregnant adults when it can be pursued without severe hypoglycemia or hypoglycemia that harms health or quality of life. Some people with good health, function, and low treatment risk may appropriately pursue a lower goal. Others need a less stringent goal because the harms or burden of treatment outweigh the likely benefit.
Screening
Uses population thresholds to identify normal, prediabetes, or diabetes-range laboratory results.
Confirmation
Determines whether an abnormal result is reproducible using an appropriate laboratory testing pathway.
Management
Sets an individualized goal after diagnosis and reviews glucose patterns, safety, and treatment burden.
Why an abnormal screening result may need confirmation
If a person does not have clear symptoms of diabetes, an A1C in the diabetes range is generally confirmed. A clinician may repeat A1C or use another accepted laboratory test, such as fasting plasma glucose or a two-hour oral glucose tolerance test. Different tests assess glucose in different ways, so occasionally they do not classify a person identically.
Diagnosis should use an appropriate laboratory method. NIDDK notes that the diagnostic A1C method should be NGSP-certified and standardized to the DCCT assay. A home A1C kit, calculator, wearable estimate, or ordinary point-of-care result should not be assumed to meet the laboratory requirements for diagnosis.
Symptoms such as marked thirst, frequent urination, unexplained weight loss, or signs of severe hyperglycemia need prompt medical evaluation. Do not wait for an online chart to decide whether urgent testing is necessary.
How clinicians individualize an A1C goal
A useful goal balances the benefit of reducing prolonged hyperglycemia against hypoglycemia, side effects, complexity, cost, and daily treatment burden. Factors include duration and type of diabetes, cardiovascular and kidney disease, cognitive and functional status, life expectancy, medications that can cause low glucose, access to monitoring, and the person’s preferences and support system.
Age alone does not select a target. In the 2026 older-adult framework, healthy older adults with few stable chronic illnesses and intact cognitive and functional status may have a reasonable A1C goal below about 7.0%–7.5%. A less stringent goal such as below 8% may be considered for significant functional or cognitive limitations, frailty, severe comorbidities, or an unfavorable treatment risk-to-benefit ratio. For very complex or poor health, the framework advises avoiding reliance on A1C and focusing on preventing hypoglycemia and symptomatic hyperglycemia.
These examples explain why a universal “A1C by age” table can be misleading. Two people of the same age may have different health, medication risk, priorities, and capacity to manage a complex regimen. A goal should be documented with the clinician who knows those details and revisited as circumstances change.
Pregnancy uses a separate framework
Pregnancy changes red-blood-cell turnover, glucose targets, medication considerations, and the risks associated with high and low glucose. The ADA 2026 pregnancy standards state that A1C is slightly lower during pregnancy and emphasize fasting, pre-meal, and after-meal glucose monitoring. For people with diabetes in pregnancy, an A1C below 6% may be ideal if achieved without significant hypoglycemia, with relaxation toward below 7% when needed to prevent hypoglycemia.
Those figures are not instructions for self-treatment and do not diagnose gestational diabetes. Pregnancy planning and diabetes in pregnancy require individualized obstetric and diabetes care. Anyone pregnant or trying to conceive should use the goals set by their care team rather than a general adult chart.
When A1C may not reflect glucose accurately
A1C depends on both glucose exposure and red-blood-cell biology. Conditions that shorten red-cell survival can lower the result relative to actual glucose, while other changes may raise or otherwise distort it. Recent blood loss, transfusion, anemia, kidney failure, erythropoietin therapy, pregnancy, and some hemoglobin variants are examples that may require a different interpretation or testing approach.
The laboratory method matters for certain hemoglobin variants. Race or ancestry should not be used as a shortcut for assuming that a result is inaccurate; the clinician can review the specific assay and relevant medical history. When the relationship between A1C and glycemia is altered, current standards advise using appropriate plasma glucose criteria for diagnosis.
A discordant result deserves investigation, not automatic dismissal. Compare A1C with a sufficiently complete glucose record. Consider whether glucose changed recently and whether monitoring missed important hours. A clinician may repeat the test, review the assay, use plasma glucose testing, or consider other markers where appropriate.
What to do with your result
Below 5.7%
Keep the report with your health records. Screening timing still depends on age, risk factors, prior results, pregnancy history, medications, and clinician guidance.
5.7%–6.4%
Arrange follow-up rather than treating the number as a diagnosis you must manage alone. Discuss confirmation, overall risk, and an evidence-based prevention plan.
6.5% or higher
Contact a clinician for timely assessment and appropriate confirmation unless a diagnosis has already been established. Seek urgent care for severe symptoms or very high glucose.
Already diagnosed
Compare the result with your documented personal goal, glucose patterns, low-glucose events, medication effects, and the changes made since the previous test.
To translate a result into estimated average glucose, use the A1C conversion chart. For day-specific fasting and after-meal information, see the separate blood sugar chart.
Safety note: do not start, stop, or change insulin or another glucose-lowering medicine from an A1C category alone. A1C cannot reveal current glucose or an immediate low. Follow your prescribed glucose plan and seek urgent help for severe symptoms.
A1C levels questions
What is considered a normal A1C?
For screening people who do not have diabetes, an A1C below 5.7% is in the normal range. A normal result does not eliminate future risk or explain symptoms by itself.
Is 5.7% A1C already diabetes?
No. An A1C from 5.7% through 6.4% is in the prediabetes range. Risk generally rises as the result approaches 6.5%, but the number should be interpreted with other clinical information.
Does one A1C of 6.5% confirm diabetes?
Usually not when there are no unequivocal symptoms. Diagnosis generally requires confirmation with a repeat A1C or another accepted laboratory glucose test on a different sample.
Should everyone with diabetes aim below 7%?
Below 7% is appropriate for many nonpregnant adults, but not everyone. Benefits, hypoglycemia, treatment burden, health status, pregnancy, and personal circumstances can justify a different goal.
Does A1C need fasting?
No. Blood for A1C can be collected without fasting. Fasting is required for some other glucose tests, so follow the instructions for every ordered test.
Can A1C diagnose type 1 or gestational diabetes?
A1C alone should not be used to diagnose type 1 diabetes, gestational diabetes, or cystic-fibrosis-related diabetes. These situations require the appropriate clinical and glucose-testing pathway.
Sources and review date
Screening and confirmation guidance: NIDDK, The A1C Test & Diabetes. Current goals and individualization: ADA Standards of Care in Diabetes—2026, Glycemic Goals, Older Adults, and Diabetes in Pregnancy. Reviewed August 15, 2026. Educational information only.