What Are Good Glucose Numbers by Category?

A good fasting blood glucose level for someone without diabetes is 70 to 99 mg/dL. That single number is the starting point, but “good” depends on when you last ate, whether you have diabetes, your age, and whether you’re pregnant. Here’s a full breakdown of what the numbers mean in every common scenario.

Healthy Fasting Glucose

If you don’t have diabetes, a fasting blood sugar between 70 and 99 mg/dL (3.9 to 5.5 mmol/L) is considered normal. “Fasting” means you haven’t eaten for at least eight hours, which is why this test is typically done first thing in the morning. Some people, particularly those who are lean or active, naturally run in the 50 to 70 mg/dL range without any symptoms, and that’s normal too.

Once fasting glucose reaches 100 to 125 mg/dL, you’re in the prediabetes range. A fasting reading of 126 mg/dL or higher on two separate occasions meets the threshold for a diabetes diagnosis.

What A1C Tells You That a Single Reading Can’t

A single glucose reading is a snapshot. Your A1C is more like a three-month average. It measures the percentage of your red blood cells that have sugar attached to them, which reflects your overall blood sugar control over roughly 90 days.

Normal: below 5.7%
Prediabetes: 5.7% to 6.4%
Diabetes: 6.5% or higher

You can convert A1C to an estimated average glucose using a simple formula: multiply the A1C percentage by 28.7, then subtract 46.7. So an A1C of 6% translates to an average glucose of about 126 mg/dL. At 7%, that average climbs to 154 mg/dL. At 8%, it’s roughly 183 mg/dL. This conversion helps you connect the A1C percentage to the kind of numbers you’d see on a home glucose meter.

Targets If You Have Diabetes

The American Diabetes Association’s 2025 guidelines set these targets for most nonpregnant adults with diabetes:

Before meals: 80 to 130 mg/dL
Two hours after starting a meal: below 180 mg/dL
A1C: below 7%

These numbers are looser than the ranges for someone without diabetes, and that’s intentional. Pushing glucose too aggressively toward “normal” levels with medication increases the risk of dangerous lows. The goal is a balance: low enough to prevent long-term complications to your eyes, kidneys, and nerves, but not so low that you’re constantly battling hypoglycemia.

Adjusted Targets for Older Adults

For healthy older adults on diabetes medication, an A1C below 7.5% with fasting glucose between 140 and 150 mg/dL is a reasonable target. For older adults with multiple health conditions or limited life expectancy, the goal relaxes further to an A1C of 8% or below, with fasting values between 160 and 170 mg/dL. In cases of severe illness or cognitive decline, targets may go as high as an A1C of 8.5%, which corresponds to an average glucose around 200 mg/dL. The priority shifts from tight control to avoiding both dangerous lows and extreme highs above 350 mg/dL.

After-Meal Numbers

Blood sugar always rises after you eat. In someone without diabetes, it typically peaks about 60 to 90 minutes after a meal and rarely goes above 140 mg/dL. The body releases insulin quickly, and levels return to baseline within two to three hours.

If you have diabetes, the CDC’s general target is to stay below 180 mg/dL two hours after starting a meal. But lower is better if you can get there without medication side effects. Consistently spiking above 180 mg/dL after meals contributes to a higher A1C even if your fasting numbers look fine, which is why checking after meals (not just in the morning) gives a more complete picture.

When Blood Sugar Drops Too Low

Low blood sugar, or hypoglycemia, is defined as anything below 70 mg/dL. At this level you might feel shaky, sweaty, irritable, or suddenly hungry. Below 54 mg/dL is considered clinically significant and can cause confusion, blurred vision, or difficulty speaking. Severe hypoglycemia, where you need someone else’s help to recover, is the most dangerous level and can lead to seizures or loss of consciousness.

If you don’t take insulin or diabetes medication, true hypoglycemia is uncommon. Most people who feel lightheaded before lunch are experiencing a normal dip, not a dangerous low. But if you’re on insulin or certain oral diabetes medications, knowing these thresholds matters because lows can come on fast.

Continuous Glucose Monitors and Time in Range

If you wear a continuous glucose monitor (CGM), you’ll see a metric called “time in range.” This measures what percentage of the day your glucose stays between 70 and 180 mg/dL. For most adults with diabetes, the goal is to spend at least 70% of the day in that window, which works out to roughly 17 out of 24 hours.

Equally important is minimizing time spent low. The recommendation is to spend less than 4% of the day below 70 mg/dL and less than 1% below 54 mg/dL. For older adults, the low-time target is even stricter: no more than 1% of the day below 70 mg/dL, or about 15 minutes total. On the high end, you want less than 25% of readings above 180 mg/dL and less than 5% above 250 mg/dL.

Time in range has become a popular metric because it captures the full picture of glucose control, including overnight swings and post-meal spikes, rather than relying on a few finger-stick snapshots per day.

Glucose Targets During Pregnancy

Pregnancy changes the numbers. Gestational diabetes screening typically happens between weeks 24 and 28 with a glucose challenge test, where you drink a sugary solution and have your blood drawn one hour later. A result below 140 mg/dL is normal. A result of 180 mg/dL or above is enough to diagnose gestational diabetes on its own. Values between 140 and 179 mg/dL require a longer follow-up test.

That follow-up is a three-hour test with four blood draws. The diagnostic cutoffs are: fasting below 95 mg/dL, one hour below 180 mg/dL, two hours below 155 mg/dL, and three hours below 140 mg/dL. Meeting or exceeding two or more of those values confirms a diagnosis. Glucose targets during pregnancy are tighter than standard diabetes targets because even moderately elevated blood sugar can affect the baby’s growth and delivery.