A healthy fasting blood glucose level is below 100 mg/dL (5.6 mmol/L). That’s the number most people are looking for, measured after at least 8 hours without eating. But “what should my blood glucose be” depends on when you last ate, whether you’re pregnant, your age, and whether you already have diabetes. Here’s a breakdown of every target that matters.
Fasting Blood Glucose Targets
Fasting blood glucose is the most common test your doctor will order, and it’s the simplest snapshot of how your body handles sugar. The ranges break down into three categories:
- 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
If your fasting number lands in the prediabetes range, your body is already struggling to move sugar out of your bloodstream efficiently. That doesn’t mean diabetes is inevitable. It means you’re in a window where changes to diet, exercise, and weight can pull that number back down. If your reading hits 126 mg/dL or above, your doctor will want to confirm it with a second test on a different day before making a diagnosis.
After-Meal Blood Glucose
Your blood sugar naturally rises after eating, then drops back down as insulin does its job. For people without diabetes, blood glucose typically peaks about an hour after a meal and returns close to baseline within two to three hours. Most people won’t notice any symptoms from post-meal spikes unless levels climb above 180 to 200 mg/dL, which is the threshold where high blood sugar tends to produce noticeable effects like increased thirst, frequent urination, or blurred vision.
If you have diabetes and are checking your numbers at home, the general target is to stay below 180 mg/dL one to two hours after eating. Your specific target may be tighter or more relaxed depending on your treatment plan.
A1C: Your 2-to-3-Month Average
While a fasting test captures a single moment, the A1C test reflects your average blood sugar over the past two to three months. It measures the percentage of your red blood cells that have sugar attached to them, giving a longer-term picture of blood sugar control. You don’t need to fast for this test.
- Normal: below 5.7%
- Prediabetes: 5.7% to 6.4%
- Diabetes: 6.5% or above
Each percentage point on the A1C scale corresponds to a specific estimated average glucose. An A1C of 5% translates to an average blood sugar of roughly 97 mg/dL. At 6%, that average climbs to about 126 mg/dL. By 7%, the average sits around 154 mg/dL, and at 8% it reaches 183 mg/dL. If you already have diabetes, most guidelines set the goal at an A1C below 7%, though your doctor may adjust that target based on your overall health and risk of low blood sugar episodes.
When Blood Sugar Drops Too Low
Low blood sugar, or hypoglycemia, is defined as anything below 70 mg/dL. At that level, you need to act quickly by eating or drinking something that raises your glucose, like juice, glucose tablets, or a few pieces of candy. Symptoms include shakiness, sweating, confusion, irritability, and a fast heartbeat.
Severe low blood sugar is below 54 mg/dL. At this point, you may lose consciousness or be unable to treat yourself, and you’ll likely need someone else to help. This is most common in people taking insulin or certain diabetes medications, not in people with normal blood sugar regulation. If you don’t take diabetes medication, a reading below 70 is unusual and worth discussing with your doctor.
Targets During Pregnancy
Blood sugar targets are tighter during pregnancy because even moderately elevated glucose can affect the baby’s development. Women with gestational diabetes are typically asked to keep their fasting glucose at or below 90 to 95 mg/dL. After meals, the target is at or below 140 mg/dL at the one-hour mark, or at or below 120 mg/dL at two hours.
These numbers are noticeably stricter than the targets for people with type 2 diabetes outside of pregnancy. Frequent monitoring, often four or more times per day, is standard for managing gestational diabetes. Most women see their blood sugar return to normal after delivery, though having gestational diabetes does increase the risk of developing type 2 diabetes later in life.
How Targets Shift for Older Adults
For older adults, especially those who are frail or managing multiple health conditions, blood sugar targets are often relaxed. Most guidelines suggest an A1C below 7.0% to 7.5% for healthier older adults, but allow a more lenient target of below 8.0% to 8.5% for those who are frail or medically complex.
The reasoning is straightforward: older adults are more vulnerable to the dangers of low blood sugar. A hypoglycemic episode that causes dizziness or fainting can lead to a serious fall. Studies have found that age and frailty increase both the risk of severe hypoglycemia and the mortality associated with it. For many older adults, avoiding dangerous lows matters more than hitting the tightest possible targets.
Continuous Glucose Monitors and Time in Range
If you wear a continuous glucose monitor (CGM), your blood sugar data is measured differently than a single finger-stick test. Instead of isolated readings, you get a continuous stream of data, and the key metric becomes “time in range,” meaning the percentage of the day your glucose stays between 70 and 180 mg/dL.
The goal for most people with type 1 or type 2 diabetes is to spend at least 70% of the day in that range. That works out to roughly 17 out of every 24 hours. CGMs also make it easy to spot patterns: you can see how specific meals, exercise, stress, or sleep affect your glucose in real time. For people managing diabetes day to day, that pattern recognition is often more useful than any single number.
Quick Reference by Test Type
- Fasting glucose (no diabetes): below 100 mg/dL
- Fasting glucose (prediabetes): 100 to 125 mg/dL
- Fasting glucose (diabetes threshold): 126 mg/dL or higher
- A1C (no diabetes): below 5.7%
- A1C (prediabetes): 5.7% to 6.4%
- A1C (diabetes goal): below 7% for most adults
- Low blood sugar: below 70 mg/dL
- Severe low blood sugar: below 54 mg/dL
- Post-meal target (diabetes): below 180 mg/dL
- Time in range (CGM): at least 70% between 70 and 180 mg/dL