A good fasting blood sugar level for someone without diabetes is 70 to 99 mg/dL. After eating, blood sugar naturally rises and should stay below 140 mg/dL in healthy adults within about two hours. These two numbers, fasting and post-meal, are the benchmarks most people need to know.
But “good” depends on context. Whether you’re healthy, managing diabetes, or pregnant, the target ranges shift. Here’s what each number means and where yours should fall.
Healthy Fasting Blood Sugar
When you haven’t eaten for at least eight hours, your blood sugar reflects your body’s baseline ability to regulate glucose. For adults without diabetes, the healthy fasting range is 70 to 99 mg/dL. Some people naturally sit between 50 and 70 mg/dL without symptoms, and that can be normal too.
Once fasting glucose reaches 100 to 125 mg/dL, it falls into the prediabetes range. This means your body is starting to struggle with insulin, the hormone that moves sugar from your blood into your cells. A fasting reading above 125 mg/dL on more than one occasion typically leads to a diabetes diagnosis.
Blood Sugar After Meals
Your blood sugar peaks roughly 60 to 90 minutes after you start eating, then gradually comes back down. In a healthy person, that peak rarely exceeds 140 mg/dL and returns close to baseline within two to three hours. The general clinical threshold is below 180 mg/dL two hours after a meal, though most people without diabetes stay well under that.
What you eat matters. A meal heavy in refined carbohydrates (white bread, sugary drinks, pastries) will spike blood sugar faster and higher than one built around protein, fiber, and healthy fats. The size of the spike and how quickly it resolves gives a more complete picture of metabolic health than fasting glucose alone.
A1C: Your Three-Month Average
A single blood sugar reading is a snapshot. The A1C test provides the bigger picture by measuring the percentage of your red blood cells that have glucose attached to them, which reflects your average blood sugar over roughly three months.
For someone without diabetes, a normal A1C is below 5.7%. Between 5.7% and 6.4% indicates prediabetes. An A1C of 6.5% or higher on two separate tests confirms diabetes.
To put those percentages in practical terms, here’s what they translate to in daily blood sugar:
- A1C of 6% = average blood sugar of about 126 mg/dL
- A1C of 7% = average blood sugar of about 154 mg/dL
- A1C of 8% = average blood sugar of about 183 mg/dL
- A1C of 9% = average blood sugar of about 212 mg/dL
Each 1% increase in A1C corresponds to roughly a 28 to 29 mg/dL jump in average glucose. If your A1C is 5.7%, your average blood sugar is sitting around 117 mg/dL, a level that looks fine on any single test but, sustained over months, signals early metabolic trouble.
Targets for People With Diabetes
If you’ve been diagnosed with diabetes, the target ranges are broader than for someone without it. The general guideline many clinicians use is a fasting glucose of 80 to 130 mg/dL and a post-meal reading below 180 mg/dL. An A1C goal of below 7% is common, but this varies widely from person to person.
The American Diabetes Association emphasizes that targets should be individualized. Your ideal range depends on how long you’ve had diabetes, your age, whether you have heart disease or other complications, and how prone you are to low blood sugar episodes. Someone who is younger and otherwise healthy may aim for tighter control (closer to non-diabetic numbers), while an older adult with multiple health conditions might have more relaxed targets to avoid the risks of blood sugar dropping too low.
Targets During Pregnancy
Pregnancy tightens the acceptable ranges considerably because elevated blood sugar affects fetal development. For women with gestational diabetes, the recommended targets are:
- Fasting or before meals: 95 mg/dL or lower
- One hour after eating: 140 mg/dL or lower
- Two hours after eating: 120 mg/dL or lower
Women who had type 1 or type 2 diabetes before becoming pregnant aim for even stricter control: fasting glucose of 60 to 99 mg/dL, post-meal peaks of 100 to 129 mg/dL, and an A1C below 6%. These tight ranges reduce the risk of complications, but they also increase the chance of blood sugar dipping too low, so they require careful monitoring and frequent adjustments.
When Blood Sugar Goes Too Low
Low blood sugar, called hypoglycemia, generally starts causing symptoms below 70 mg/dL. You might feel shaky, sweaty, dizzy, irritable, or suddenly hungry. Your heart may race. Below 54 mg/dL is considered serious and can cause confusion, blurred vision, or difficulty speaking. Extremely low levels can lead to seizures or loss of consciousness.
Hypoglycemia is most common in people taking insulin or certain diabetes medications, but it can happen to anyone after prolonged fasting, intense exercise, or heavy alcohol consumption on an empty stomach. If you feel symptoms, eating 15 to 20 grams of fast-acting carbohydrates (a few glucose tablets, half a cup of juice, or a tablespoon of honey) will typically bring levels back up within 15 minutes.
When Blood Sugar Goes Too High
For someone without a diabetes diagnosis, fasting blood sugar above 125 mg/dL qualifies as hyperglycemia. For someone with diabetes, readings above 180 mg/dL one to two hours after eating are considered high. People with type 1 diabetes often have blood sugar above 250 mg/dL at the time of diagnosis.
Mild hyperglycemia may not produce any noticeable symptoms, which is why it often goes undetected for years. As levels climb, you might notice increased thirst, frequent urination, fatigue, blurry vision, or headaches. Chronically elevated blood sugar, even at levels that feel “fine” day to day, damages blood vessels and nerves over time. This is why catching prediabetes early matters: the damage begins before blood sugar crosses the diabetes threshold.
Quick Reference: Blood Sugar Ranges
- Normal fasting: 70 to 99 mg/dL
- Prediabetes fasting: 100 to 125 mg/dL
- Diabetes fasting: 126 mg/dL or higher (on two tests)
- Normal after eating (2 hours): below 140 mg/dL
- Normal A1C: below 5.7%
- Prediabetes A1C: 5.7% to 6.4%
- Diabetes A1C: 6.5% or higher
- Low blood sugar: below 70 mg/dL
These ranges apply to venous blood draws and standard glucose meters. Continuous glucose monitors may read slightly differently since they measure glucose in the fluid between cells rather than in blood directly. If your readings consistently fall outside these ranges, even by a small margin, it’s worth getting a formal blood draw to confirm.