A good fasting blood sugar reading is 99 mg/dL or below. After a meal, a healthy reading stays under 140 mg/dL when measured two hours later. These are the benchmarks for adults without diabetes, but “good” shifts depending on whether you’re managing diabetes, pregnant, or older with other health conditions.
Fasting Blood Sugar: The Baseline Number
Fasting blood sugar is measured after at least eight hours without eating, typically first thing in the morning. For a healthy adult, 99 mg/dL or below is normal. Readings between 100 and 125 mg/dL fall into the prediabetes range, and 126 mg/dL or higher on two separate tests indicates diabetes.
If you have diabetes and are checking your sugar before meals, the target is a bit wider: 80 to 130 mg/dL. That range accounts for the reality that tighter control in someone on medication can cause blood sugar to drop too low, which carries its own risks.
After-Meal Readings
Blood sugar naturally rises after you eat. In someone without diabetes, it peaks about an hour after a meal and returns close to baseline within two hours. A reading under 140 mg/dL at the two-hour mark is considered normal.
For people managing diabetes, the goal is to stay under 180 mg/dL at peak, which typically happens one to two hours after your first bite. If you’re consistently above that, it may signal that your meal plan or treatment needs adjusting.
A1C: The Bigger Picture
While finger-stick readings capture a single moment, the A1C test reflects your average blood sugar over roughly two to three months. It’s reported as a percentage. For most adults with diabetes, the goal is an A1C below 7%, which corresponds to an estimated average glucose of about 154 mg/dL. A normal A1C for someone without diabetes is below 5.7%, and 5.7% to 6.4% signals prediabetes.
Here’s how A1C percentages translate to daily averages:
- 6%: ~126 mg/dL
- 7%: ~154 mg/dL
- 8%: ~183 mg/dL
- 9%: ~212 mg/dL
- 10%: ~240 mg/dL
Some people can safely aim lower. An A1C under 6.5% may be appropriate if you’re in good health, your treatment plan doesn’t put you at risk for low blood sugar, and you’re managing well. Others benefit from a more relaxed target, which we’ll get to below.
Time in Range for Continuous Monitors
If you wear a continuous glucose monitor (CGM), the key metric is “time in range,” meaning the percentage of the day your blood sugar stays between 70 and 180 mg/dL. The goal for most adults with type 1 or type 2 diabetes is to spend more than 70% of the day in that window, which works out to roughly 17 hours.
Equally important is avoiding lows. You want less than 4% of readings below 70 mg/dL and less than 1% below 54 mg/dL. Those thresholds matter because low blood sugar can cause shakiness, confusion, and in severe cases, loss of consciousness.
When Blood Sugar Drops Too Low
Good readings aren’t just about avoiding highs. Blood sugar below 70 mg/dL is considered low (hypoglycemia) and typically causes symptoms like sweating, a racing heart, irritability, or feeling shaky. Below 54 mg/dL is more serious and can impair your ability to think clearly or function normally. A severe low is any episode where you need someone else’s help to recover, regardless of the exact number on the meter.
Hypoglycemia is primarily a concern for people taking insulin or certain other diabetes medications. If you don’t take those, your body generally prevents blood sugar from dropping to dangerous levels.
Targets During Pregnancy
Pregnancy tightens the targets considerably because even mildly elevated blood sugar can affect fetal development. For pregnant women with gestational diabetes or pre-existing diabetes, the goals are:
- Fasting: 70 to 95 mg/dL
- One hour after a meal: under 140 mg/dL
- Two hours after a meal: under 120 mg/dL
For those using a continuous monitor during pregnancy, the recommended time-in-range window narrows to 63 to 140 mg/dL, with at least 70% of readings falling within it.
Adjusted Goals for Older Adults
For older adults, especially those managing multiple chronic conditions or experiencing cognitive decline, the targets are intentionally relaxed. The priority shifts toward preventing low blood sugar, which poses outsized risks in this group. Falls, confusion, and even dementia risk have all been linked to repeated lows.
An older adult in otherwise good health can aim for the standard A1C under 7%. But for someone with multiple health issues, limited mobility, or mild cognitive impairment, an A1C under 8% is reasonable, with fasting readings between 90 and 150 mg/dL. For those in poor overall health or long-term care, the focus moves away from A1C entirely. The practical goal becomes keeping fasting sugar between 100 and 180 mg/dL and avoiding both symptomatic highs and dangerous lows.
Children and Teens
Normal blood sugar ranges for children are similar to adults. By age 2 and beyond, a fasting range of 60 to 100 mg/dL is typical. Infants naturally run a bit lower, with normal readings between 40 and 90 mg/dL. For children with type 1 diabetes, the same general targets used for adults (A1C under 7%, time in range above 70%) apply in most cases, though the care team may individualize based on the child’s age and risk of lows.
What Affects Your Readings
Even in a completely healthy person, blood sugar isn’t static. It fluctuates based on what you ate, when you ate, how much you slept, your stress level, physical activity, and even the time of day. A single high reading doesn’t mean something is wrong, and a single normal reading doesn’t guarantee everything is fine. Patterns over time matter far more than any individual number.
If you’re checking at home, technique matters too. Dirty or wet hands, expired test strips, and extreme temperatures can all skew readings. Washing your hands before testing (rather than using an alcohol swab, which can interfere) gives the most reliable result. And if a reading seems surprisingly high or low but you feel fine, testing again before reacting is a reasonable step.