HbA1c Normal Range, A1c Levels Chart & What Your Results Mean

Glucose in your bloodstream sticks to hemoglobin, the protein inside red blood cells that carries oxygen. The more glucose floating around, the more hemoglobin gets "glycated" — coated with sugar. Your A1c percentage reflects how much of your hemoglobin has glucose attached.

Red blood cells live about 120 days. So at any given time, your blood contains cells of different ages, each carrying a record of the glucose they've been exposed to. The A1c test reads that record. Recent weeks weigh more heavily than older ones, but you're still getting roughly a 3-month window.

One number. Three months of data. No fasting required.

These thresholds come from the American Diabetes Association (ADA) and CDC. They apply to non-pregnant adults using a standardized lab assay.

• Below 5.7% — Normal. Your glucose regulation is working well.
• 5.7% to 6.4% — Prediabetes. Insulin resistance is building. About 70% of people in this range eventually develop type 2 diabetes if nothing changes — but lifestyle intervention cuts that risk by more than half.
• 6.5% or higher — Diabetes. Two separate tests at or above 6.5% confirm the diagnosis (unless you already have classic symptoms like excessive thirst and frequent urination).

For people already diagnosed with diabetes, the ADA recommends a target below 7.0% for most adults. Older patients or those at risk of hypoglycemia may aim for a higher target, sometimes below 8.0%, in discussion with their doctor.

A high A1c usually signals that blood sugar has been elevated over the past few months. But a high A1c doesn't always mean diabetes.

Several conditions push A1c up without affecting your actual blood sugar:

• Iron deficiency anemia — the most common non-diabetic cause. Fewer healthy red blood cells means each one lives longer and accumulates more glucose. Fix the iron deficiency, and A1c drops.
• B12 or folate deficiency — same mechanism as iron deficiency.
• Chronic kidney disease — uremic compounds interfere with the assay itself.
• Splenectomy — without a spleen clearing old red blood cells, they hang around longer.
• High-dose aspirin (above 200 mg/day) — acetylation of hemoglobin can add roughly 0.17% to your result.

If your A1c is elevated but your fasting glucose and oral glucose tolerance test are normal, ask your doctor about these possibilities. A fructosamine test — which measures glycated proteins over 2 to 3 weeks — can confirm whether elevated glucose is truly the cause.

When A1c is reflecting real hyperglycemia, the risks scale with the number. An A1c of 7% carries meaningfully lower cardiovascular and kidney risk than an A1c of 9%. Every percentage point you bring it down matters.

This one catches people off guard. Certain conditions make A1c look better than it should:

• Hemolytic anemias — red blood cells are destroyed faster, so there's less time for glucose to accumulate on hemoglobin.
• Recent blood loss or transfusion — fresh or donor red blood cells dilute the glycated ones.
• Pregnancy — red blood cell lifespan drops from ~120 to ~90 days, and increased blood volume shifts the balance. A1c naturally decreases by the second trimester.
• Liver disease — altered hemoglobin metabolism affects glycation.
• Erythropoietin therapy — rapid production of new red blood cells means a younger, less-glycated population.

A person with sickle cell trait (about 8% of Black Americans carry HbAS) may get unreliable A1c results depending on the lab method used. Homozygous hemoglobin variants like HbSS make A1c essentially useless — fructosamine or a continuous glucose monitor (CGM) should be used instead.

So a "normal" A1c isn't always reassuring if you have a condition that shortens red blood cell lifespan. Context matters.

Most A1c articles stop at the ranges table. But a single A1c is a snapshot — and lab variability alone can swing it by 0.5% in either direction. You could test at 5.9% in March and 5.4% in June with zero actual change in your glucose control.

The real story is in the trajectory.

Consider three people, all with an A1c of 6.0% today:

• Person A: Last three readings were 5.5%, 5.7%, 6.0%. That's a clear upward drift. At this rate, they'll cross into diabetes territory within a year or two.
• Person B: Last three readings were 6.4%, 6.2%, 6.0%. They made changes, and those changes are working. Encouraging.
• Person C: Last three readings were 6.1%, 5.9%, 6.0%. Basically flat. Stable prediabetes — not worsening, but not improving either.

Same number today. Three completely different stories. You can't see any of that from a single test.

When you upload your lab results to AskAnything, each A1c reading gets plotted on a trend chart (LOINC code 4548-4). Over time, the pattern becomes obvious — rising, falling, or plateaued. That trajectory is far more useful than any single reading.

A1c-to-eAG conversion — this makes the number more intuitive. The formula is eAG (mg/dL) = 28.7 x A1c - 46.7. Some quick reference points:

• A1c 5.0% = ~97 mg/dL average glucose
• A1c 5.7% = ~117 mg/dL
• A1c 6.0% = ~126 mg/dL
• A1c 6.5% = ~140 mg/dL
• A1c 7.0% = ~154 mg/dL
• A1c 8.0% = ~183 mg/dL
• A1c 9.0% = ~212 mg/dL
• A1c 10.0% = ~240 mg/dL

If you check your blood sugar with a finger-stick meter, compare your average readings against your A1c's eAG. A big mismatch can flag issues — either with A1c accuracy (see the falsely high/low sections above) or with when you're checking glucose (only testing fasting but missing post-meal spikes, for example).

Not every result outside the "normal" box is an emergency. But some patterns deserve a conversation sooner rather than later:

• A1c above 6.5% on a first test — get it confirmed with a second test. Don't panic, but don't wait six months either.
• A1c rising by 0.3% or more per year — even within the prediabetes range, this pace of increase is clinically significant.
• A1c not dropping after 3 months on metformin — metformin typically lowers A1c by 1.0 to 1.5 percentage points. If you've been on it for a full quarter and the number hasn't budged, bring that up. Dose, adherence, or an additional medication might need discussion.
• A1c above 9% — this level carries serious risk for complications (retinopathy, neuropathy, kidney damage). Aggressive treatment is usually warranted.
• Mismatch between A1c and daily glucose readings — if your meter says you're averaging 110 mg/dL but your A1c implies 183 mg/dL, something is off. You might have a condition causing falsely high A1c, or you might be missing post-meal spikes that the meter doesn't catch.

One more thing: the ADA recommends screening at age 45, or younger if you have risk factors (BMI over 25, family history of diabetes, history of gestational diabetes, or PCOS). If you've never had your A1c checked and any of those apply, it's worth asking for one at your next visit.

Fasting Plasma Glucose (LOINC 1558-6) — a point-in-time blood sugar after an 8-hour fast. Used alongside A1c for diagnosis. Normal is below 100 mg/dL; 100-125 is prediabetes; 126+ is diabetes.

Fructosamine (LOINC 4549-2) — measures glycated proteins over the past 2 to 3 weeks. Your go-to alternative when A1c can't be trusted (hemoglobin variants, recent transfusion, pregnancy).

C-Peptide (LOINC 1986-9) — tells you how much insulin your pancreas is actually producing. Useful for distinguishing type 1 from type 2 diabetes and for gauging beta-cell function over time.

Fasting Insulin (LOINC 2484-4) — paired with fasting glucose, this lets your doctor calculate HOMA-IR, a measure of insulin resistance. Helpful for catching metabolic trouble before A1c rises.

Oral Glucose Tolerance Test — the gold standard for gestational diabetes and useful when A1c results are borderline. Measures glucose response 2 hours after drinking a 75g glucose solution.

A1c doesn't exist in a vacuum. If your results seem off or you want the full metabolic picture, these tests fill in the gaps.