Good blood sugar levels for a healthy adult fall below 100 mg/dL when fasting and below 140 mg/dL two hours after eating. These numbers shift depending on your age, whether you’re pregnant, and whether you have diabetes. Here’s what each range means and how the targets change in different situations.
Normal Blood Sugar for Healthy Adults
If you don’t have diabetes, three tests define where you stand. A fasting blood sugar test, taken after at least eight hours without food, should come in at 99 mg/dL or below. A glucose tolerance test, which measures your blood sugar two hours after drinking a sugary solution, should read 140 mg/dL or below. And an A1C test, which reflects your average blood sugar over the past two to three months, should be below 5.7%.
After a regular meal, your blood sugar naturally rises. In a person without diabetes, it peaks somewhere around the one-hour mark and settles back below 140 mg/dL by the two-hour point. You won’t feel any symptoms at these levels because your body is efficiently clearing glucose from the bloodstream.
Prediabetes: The In-Between Zone
Prediabetes means your blood sugar is higher than normal but not high enough to qualify as diabetes. The specific cutoffs, based on the American Diabetes Association’s 2025 standards, are:
- Fasting blood sugar: 100 to 125 mg/dL
- A1C: 5.7% to 6.4%
- Glucose tolerance test (2-hour): 140 to 199 mg/dL
Any one of those results is enough for a prediabetes diagnosis. This stage is reversible for many people through changes in diet, physical activity, and weight. It’s not a guarantee of diabetes, but it does signal that your body is starting to struggle with processing sugar.
Target Ranges if You Have Diabetes
Once you have a diabetes diagnosis, the definition of “good” shifts upward. The goal is no longer to match a non-diabetic body perfectly but to stay in a range that prevents complications without pushing you into dangerously low blood sugar. The CDC outlines these typical targets for adults with diabetes:
- Before a meal: 80 to 130 mg/dL
- Two hours after starting a meal: below 180 mg/dL
- A1C: below 7%, which translates to an estimated average glucose of about 154 mg/dL
These targets work well for most adults, but your care team may adjust them based on how long you’ve had diabetes, what medications you take, and your risk of low blood sugar episodes.
When Blood Sugar Drops Too Low
Blood sugar below 70 mg/dL is considered low, a condition called hypoglycemia. At this level you might feel shaky, sweaty, dizzy, or unusually hungry. Below 54 mg/dL is classified as severe, and it can cause confusion, difficulty speaking, seizures, or loss of consciousness. Low blood sugar is most common in people who take insulin or certain oral diabetes medications, but it can happen to anyone who goes long stretches without eating or exercises intensely on an empty stomach.
If you notice symptoms, fast-acting carbohydrates like juice, glucose tablets, or regular soda can bring your levels back up within 15 to 20 minutes. Recheck after that window and eat a small snack with protein to keep things stable.
When Blood Sugar Climbs Too High
On the other end, symptoms of high blood sugar typically don’t appear until levels exceed 180 to 200 mg/dL. That’s part of what makes diabetes tricky: you can walk around with elevated glucose for months or years without obvious warning signs. When symptoms do show up, they usually include increased thirst, frequent urination, blurry vision, fatigue, and slow-healing cuts.
Sustained high blood sugar, even without symptoms, damages blood vessels and nerves over time. This is why A1C matters so much. A single high reading after a big meal is not the same as running high all day, every day. The A1C captures the bigger picture.
Blood Sugar Targets During Pregnancy
Pregnancy tightens the acceptable range significantly because elevated blood sugar affects fetal development. Whether you have gestational diabetes or entered pregnancy with an existing diagnosis, the ADA’s 2026 standards set these goals:
- Fasting: 70 to 95 mg/dL
- One hour after a meal: 110 to 140 mg/dL
- Two hours after a meal: 100 to 120 mg/dL
These are notably tighter than the standard diabetes targets. If you have type 2 diabetes managed by diet alone, the lower end of these ranges is less of a concern since there’s little risk of medication-driven low blood sugar. For anyone on insulin during pregnancy, the goal is to stay within these windows without frequent drops below 70 mg/dL.
How Targets Change for Children
Managing blood sugar in children and adolescents with diabetes requires a different approach than in adults. The ADA recommends an A1C below 7% for most children, with the acknowledgment that this isn’t always achievable or safe. For kids who can’t recognize symptoms of low blood sugar, who lack access to continuous glucose monitors, or who have a history of severe hypoglycemic episodes, a looser target of below 7.5% or even below 8% may be more appropriate.
Before physical activity, blood sugar between 126 and 180 mg/dL gives children enough fuel to exercise safely without spiking or crashing. This range helps balance performance and safety during sports or active play.
How Targets Change for Older Adults
Older adults face a unique challenge: the risks of low blood sugar become more dangerous with age. Hypoglycemia in older adults is linked to falls, cognitive decline, and hospitalization. At the same time, irregular eating patterns and declining kidney function make blood sugar harder to control.
The ADA’s 2025 guidelines break older adults into three categories based on overall health:
- Healthy older adults (few other chronic conditions, good cognitive function): A1C below 7.0% to 7.5%, with blood sugar between 70 and 180 mg/dL at least 70% of the time.
- Complex health (multiple chronic conditions or mild cognitive impairment): A1C below 8.0%, with blood sugar between 70 and 180 mg/dL about 50% of the time and very little time spent below 70 mg/dL.
- Very complex or poor health (end-stage illness, moderate to severe cognitive impairment): A1C becomes less useful as a metric. The focus shifts entirely to avoiding both dangerous lows and symptom-causing highs.
The pattern across all age groups is the same: “good” blood sugar is whatever range keeps you safe from both immediate danger and long-term damage, given your specific health situation.