HbA1c (A1C): Normal Range and Meaning

HbA1c (also called A1C or glycated hemoglobin) measures the percentage of hemoglobin in red blood cells that has glucose attached to it, reflecting average blood sugar over roughly the past two to three months rather than a single moment in time.

Normal HbA1c Range

• Normal: below 5.7%
• Prediabetes: 5.7%–6.4%
• Diabetes: 6.5% or higher, usually confirmed with a repeat test

Why HbA1c Is Useful

Because it reflects an average rather than a single reading, HbA1c isn't affected by what you ate the day before the test, and no fasting is required. This makes it a convenient screening and monitoring tool, and it's also used to track how well diabetes treatment is working over time — many doctors recommend checking it every 3 to 6 months for people with diabetes.

What Can Make HbA1c Less Accurate

Certain conditions that affect red blood cells — including some forms of anemia, recent significant blood loss, and certain blood disorders — can make HbA1c inaccurate as a reflection of true average blood sugar. In these situations, a doctor may rely more on fasting glucose or an oral glucose tolerance test instead. Our diabetes blood tests guide compares all of these options.