A healthy fasting blood sugar level is 99 mg/dL or below. Two hours after eating, it should stay under 140 mg/dL. These are the benchmarks for adults without diabetes, but your personal target depends on whether you’re managing diabetes, pregnant, or older with other health conditions.
Normal Blood Sugar Ranges
Your body keeps blood sugar in a surprisingly tight range throughout the day. Two hormones do most of the work: insulin pushes sugar out of your blood and into cells after you eat, while glucagon pulls stored sugar back out of your liver between meals. When this system works well, your numbers fall into predictable zones.
Fasting (no food for 8+ hours): 99 mg/dL or below
Two hours after eating: less than 140 mg/dL
Blood sugar isn’t static. It rises after every meal and dips overnight. A reading of 120 mg/dL an hour after lunch is completely normal and doesn’t mean anything is wrong. What matters is where you land at baseline (fasting) and how quickly your body brings levels back down after food.
The Prediabetes Warning Zone
Between “normal” and “diabetes” sits a range that signals your body is starting to struggle with blood sugar regulation. A fasting reading between 100 and 125 mg/dL is classified as impaired fasting glucose, the hallmark of prediabetes. If a glucose tolerance test (where you drink a sugary solution and get tested two hours later) comes back between 140 and 199 mg/dL, that’s impaired glucose tolerance.
Your doctor may also check your A1C, which reflects your average blood sugar over roughly three months. The thresholds are straightforward:
- Normal: below 5.7%
- Prediabetes: 5.7% to 6.4%
- Diabetes: 6.5% or above
Prediabetes is worth paying attention to because it’s reversible. At this stage, changes to diet, exercise, and weight can pull your numbers back into the normal range before the condition progresses.
Targets if You Have Diabetes
If you’ve been diagnosed with diabetes, the goal isn’t to match the numbers of someone without the condition. The targets are intentionally wider to reduce the risk of blood sugar dropping too low, which can be dangerous in its own right.
The CDC lists these typical targets for people managing diabetes:
- Before a meal: 80 to 130 mg/dL
- Two hours after the start of a meal: less than 180 mg/dL
If you use a continuous glucose monitor (CGM), you’ll hear the term “time in range.” This measures how many hours per day your blood sugar stays between 70 and 180 mg/dL. The goal for most people is at least 70% of readings in that window, which works out to roughly 17 out of 24 hours. This metric is often more useful than any single reading because it shows how stable your blood sugar is across the full day, including overnight.
Blood Sugar During Pregnancy
Pregnancy tightens the targets considerably. High blood sugar during pregnancy can affect both the mother and the baby, so the recommended ranges are lower than standard diabetes targets.
For gestational diabetes or pre-existing diabetes during pregnancy, the American Diabetes Association recommends:
- Fasting: below 95 mg/dL
- One hour after eating: below 140 mg/dL
- Two hours after eating: below 120 mg/dL
For women with type 1 or type 2 diabetes who are pregnant, the targets include lower limits as well. Fasting glucose should stay between 70 and 95 mg/dL, and two-hour post-meal readings should fall between 100 and 120 mg/dL. The lower bounds matter here because dropping too low carries its own risks during pregnancy.
How Targets Shift With Age
For older adults managing diabetes, the standard A1C target of 7.0% or below applies if you’re generally healthy and independent. But guidelines from Diabetes Canada make clear that it’s functional status and life expectancy, not age alone, that should shape your targets.
If you’re managing multiple health conditions or need daily assistance, an A1C between 7.1% and 8.0% is reasonable. For someone who is frail or living with dementia, the target loosens further to 7.1% to 8.5%. The logic is simple: the tighter you control blood sugar, the higher the risk of a dangerous low. For someone who is frail, a severe low blood sugar episode (a fall, confusion, loss of consciousness) poses a more immediate threat than slightly elevated sugar over time.
When Blood Sugar Drops Too Low
Most conversations about blood sugar focus on highs, but lows are the more immediate emergency. Blood sugar below 70 mg/dL is considered low, and you need to act on it. Below 54 mg/dL is classified as severe and can lead to confusion, seizures, or loss of consciousness.
The early symptoms of low blood sugar feel like your body’s alarm system going off: shakiness, sweating, a fast heartbeat, sudden hunger, irritability, or feeling lightheaded. These symptoms come on quickly. If you check your blood sugar and it’s below 70, the standard response is to eat or drink 15 grams of fast-acting carbohydrates (four glucose tablets, four ounces of juice, or a tablespoon of sugar), wait 15 minutes, and recheck. This is sometimes called the “15-15 rule.”
Low blood sugar primarily affects people taking insulin or certain diabetes medications. If you don’t have diabetes and aren’t on medication that lowers blood sugar, true hypoglycemia is uncommon.
What Affects Your Numbers Day to Day
Even if you eat the same meals and follow the same routine, your blood sugar won’t be identical every day. Stress raises blood sugar because your body releases stored glucose to prepare for a perceived threat. Poor sleep does the same, reducing your cells’ sensitivity to insulin after just one night. Illness, especially infections, can spike your numbers for days.
Physical activity generally lowers blood sugar, sometimes for hours afterward, because working muscles pull glucose directly out of your bloodstream. However, intense exercise can temporarily raise it due to a stress hormone response. The timing of meals matters too. The same plate of pasta will produce a different blood sugar curve depending on whether you ate it with protein and fat or on its own, and whether you went for a walk afterward or sat on the couch.
If you’re checking your blood sugar at home, consistency in how and when you test matters more than any single reading. A fasting test means nothing if you snacked at midnight. A post-meal reading is only meaningful if you time it from the start of the meal, not the end. And one high or low number doesn’t define your health. Patterns over days and weeks tell the real story.