A healthy fasting blood glucose level is below 100 mg/dL. After eating, it should return to below 140 mg/dL within two hours. These are the benchmarks for adults without diabetes, but the targets shift depending on your age, whether you’re pregnant, and whether you’re managing diabetes.
Fasting Blood Glucose Ranges
Fasting blood glucose is measured after at least eight hours without eating, typically first thing in the morning. The thresholds are straightforward:
- Normal: below 100 mg/dL (5.6 mmol/L)
- Prediabetes: 100 to 125 mg/dL (5.6 to 6.9 mmol/L)
- Diabetes: 126 mg/dL (7.0 mmol/L) or higher on two separate tests
A single reading above 126 mg/dL doesn’t automatically mean diabetes. The second test matters because blood sugar fluctuates day to day based on stress, sleep, illness, and what you ate the night before. Two elevated readings on different days confirm a pattern rather than a fluke.
After-Meal Blood Glucose
Blood sugar naturally rises after you eat. In someone without diabetes, it peaks around 30 to 60 minutes after a meal and settles back down within a couple of hours. At the two-hour mark, a normal reading is below 140 mg/dL. If your glucose is still above 140 at that point, it suggests your body isn’t clearing sugar from the bloodstream efficiently, which can be an early sign of insulin resistance or diabetes.
The speed and size of that post-meal spike depend heavily on what you ate. A meal rich in refined carbohydrates will push glucose higher and faster than one built around protein, fat, and fiber. This is why two people with the same fasting number can have very different after-meal patterns.
Targets for People With Diabetes
If you have diabetes, the goal isn’t necessarily to match the numbers of someone without it. Targets are set to reduce long-term complications while avoiding dangerous lows. The 2025 American Diabetes Association Standards of Care recommend an A1c below 7% for most adults with diabetes, which corresponds to an estimated average glucose of about 154 mg/dL.
A1c reflects your average blood sugar over roughly three months. The conversion is fairly linear: an A1c of 6% equals an average glucose of about 126 mg/dL, 7% equals 154 mg/dL, 8% equals 183 mg/dL, and 9% equals 212 mg/dL. Each half-percent increase in A1c adds roughly 14 mg/dL to your estimated average.
For people using a continuous glucose monitor, the key metric is “time in range,” meaning the percentage of the day your glucose stays between 70 and 180 mg/dL. The target is at least 70% of readings in that window, which works out to roughly 17 out of 24 hours.
When Blood Sugar Is Too Low
Blood glucose below 70 mg/dL is considered low, a condition called hypoglycemia. Symptoms include shakiness, sweating, a fast heartbeat, confusion, and irritability. Most people start to feel “off” somewhere in the 60s, though the threshold varies. Hypoglycemia is most common in people taking insulin or certain diabetes medications, but it can also happen after prolonged fasting or intense exercise.
Treating a low is simple: consume 15 to 20 grams of fast-acting carbohydrates (glucose tablets, juice, regular soda) and recheck in 15 minutes. The danger comes when lows go unrecognized or happen during sleep, which is one reason glucose targets for some groups are intentionally set higher.
When Blood Sugar Is Dangerously High
Readings above 240 mg/dL paired with symptoms like nausea, vomiting, fruity-smelling breath, or confusion can signal a medical emergency called diabetic ketoacidosis. At that level, the body may start breaking down fat for fuel in a way that produces toxic acids in the blood. Anyone with glucose above 240 mg/dL who also has ketone symptoms needs immediate medical attention.
Persistently elevated glucose in the 200s and 300s, even without acute symptoms, causes progressive damage to blood vessels, nerves, kidneys, and eyes over months and years. This is why long-term average glucose (A1c) matters more than any single reading.
Targets During Pregnancy
Pregnancy tightens the acceptable range considerably because elevated maternal blood sugar increases the risk of the baby growing too large and of complications during delivery. Both the American Diabetes Association and the American College of Obstetricians and Gynecologists recommend these targets for pregnant women with gestational or pre-existing diabetes:
- Fasting: below 95 mg/dL
- One hour after a meal: below 140 mg/dL
- Two hours after a meal: below 120 mg/dL
The A1c goal during pregnancy is also lower, ideally below 6%, partly because red blood cell turnover increases during pregnancy and naturally lowers A1c readings. For pregnant women using a continuous glucose monitor, the target range narrows to 63 to 140 mg/dL, with less than 25% of time spent above that ceiling.
Targets for Children and Adolescents
The 2025 ADA guidelines set an A1c goal below 6.5% for most children and adolescents with diabetes, a target that has tightened in recent years as glucose monitoring technology has improved. The international pediatric diabetes guidelines from ISPAD align with this, recommending A1c at or below 6.5% for kids who have access to continuous glucose monitors and automated insulin delivery systems, and at or below 7% for everyone else.
For day-to-day numbers, the recommended pre-meal range for children is 70 to 144 mg/dL, and post-meal readings should stay between 70 and 180 mg/dL. On a continuous monitor, the same time-in-range target applies as for adults: more than 70% of readings between 70 and 180 mg/dL, with less than 4% below 70.
Targets for Older Adults
Glucose goals for people over 65 are intentionally more relaxed. The primary reason is that low blood sugar is more dangerous in older adults. They’re more likely to experience dizziness, confusion, or falls from a hypoglycemic episode, and they’re less likely to notice the early warning signs because the typical symptoms (tremors, sweating) are often muted with age, replaced by subtler signs like weakness or delirium.
The recommended targets break down by overall health status:
- Healthy older adults: A1c below 7.5%, with fasting glucose around 140 to 150 mg/dL
- Those with significant health conditions: A1c at or below 8%, with fasting glucose around 160 to 170 mg/dL
- Frail or cognitively impaired older adults: A1c below 8.5% (average glucose around 200 mg/dL), with the primary focus on avoiding both dangerously low episodes and severe highs above 350 mg/dL
Research from the ACCORD trial showed that aggressively pushing blood sugar lower in older adults with cardiovascular risk, especially through multiple medications, actually increased the risk of death. This is why the approach for older adults prioritizes safety and quality of life over hitting the tightest possible number.
What a Single Reading Tells You
Blood sugar is not a fixed number. It moves constantly throughout the day, rising after meals, dropping during exercise, climbing during stress or illness, and settling overnight. A single fingerstick gives you a snapshot, not a verdict. Two people with the same A1c can have very different daily patterns: one might have steady glucose in the 130s all day, while the other swings between 70 and 200 regularly.
If you’re checking because you’re curious about your metabolic health, a fasting reading under 100 mg/dL and an A1c under 5.7% put you squarely in the normal range. If your fasting number lands between 100 and 125, that’s the prediabetes zone, where lifestyle changes like regular exercise and reducing refined carbohydrate intake are most effective at preventing progression. The earlier you catch that drift upward, the easier it is to reverse.