A healthy blood sugar level for someone without diabetes is 70 to 99 mg/dL when measured after fasting (no food for at least 8 hours). After eating, blood sugar in a healthy person peaks around 60 minutes and rarely goes above 140 mg/dL, then returns to pre-meal levels within two to three hours. These numbers shift depending on whether you have diabetes, are pregnant, or are older with other health conditions.
Normal Fasting Blood Sugar
If you don’t have diabetes, a fasting reading between 70 and 99 mg/dL (3.9 to 5.5 mmol/L) is considered normal. Some people naturally run between 50 and 70 mg/dL without symptoms, and that can be normal too, especially overnight or first thing in the morning. The key is consistency: if your fasting numbers regularly land in the same general range and you feel fine, your body is regulating glucose well.
If your fasting blood sugar falls between 100 and 125 mg/dL on more than one test, that’s the prediabetes range. At 126 mg/dL or higher on two separate tests, the reading meets the diagnostic threshold for diabetes.
After-Meal Blood Sugar
Your blood sugar naturally rises after you eat. In someone without diabetes, it peaks about an hour after the first bite and stays below 140 mg/dL. By two to three hours later, it settles back to where it started. You don’t need to test after meals unless your doctor has asked you to, but if you do, a reading under 140 mg/dL at the two-hour mark is a good sign.
For people managing diabetes, the post-meal window matters more. Most treatment plans aim to keep blood sugar below 180 mg/dL one to two hours after eating. Tighter targets exist for specific situations like pregnancy (more on that below).
A1C: The Bigger Picture
While a finger-stick or glucose meter gives you a snapshot, the A1C test shows your average blood sugar over the past two to three months. It’s reported as a percentage, and the ranges are straightforward:
- Normal: below 5.7%
- Prediabetes: 5.7% to 6.4%
- Diabetes: 6.5% or above
Most adults with diabetes aim for an A1C under 7%, which corresponds to an average blood sugar of roughly 154 mg/dL. Your doctor may set a different target depending on your age, how long you’ve had diabetes, and your risk of low blood sugar episodes.
Targets for People With Diabetes
If you’re managing type 1 or type 2 diabetes, the goal isn’t to hit one perfect number. It’s to spend most of your day within a target range. For most adults with diabetes, that range is 70 to 180 mg/dL. If you wear a continuous glucose monitor (CGM), the international consensus recommendation is to spend at least 70% of the day, roughly 17 hours, within that window.
Equally important is minimizing time spent too low or too high. The targets call for less than 4% of the day (under one hour) below 70 mg/dL and less than 5% of the day (about 72 minutes) above 250 mg/dL. Readings above 250 mg/dL sustained over time increase the risk of a dangerous condition called diabetic ketoacidosis, and levels above 300 mg/dL that won’t come down with treatment warrant emergency care.
When Blood Sugar Drops Too Low
Low blood sugar, or hypoglycemia, is classified in three stages:
- Level 1 (mild): 54 to 69 mg/dL. You might feel shaky, sweaty, or hungry. Usually corrected by eating 15 to 20 grams of fast-acting carbohydrate.
- Level 2 (moderate): below 54 mg/dL. Symptoms get more intense: confusion, blurred vision, difficulty concentrating. This needs immediate treatment.
- Level 3 (severe): defined not by a specific number but by the inability to function. The person needs someone else’s help to recover, regardless of the reading on the meter.
Hypoglycemia is most common in people taking insulin or certain oral diabetes medications. If you don’t take these, readings in the low range are far less likely to be dangerous.
Blood Sugar During Pregnancy
Pregnant women with gestational diabetes have tighter targets because even mildly elevated blood sugar can affect fetal development. The recommended goals for gestational diabetes are:
- Fasting: 95 mg/dL or lower
- One hour after a meal: 140 mg/dL or lower
- Two hours after a meal: 120 mg/dL or lower
For women with pre-existing type 1 diabetes who become pregnant, CGM targets shift as well. The target range narrows to 63 to 140 mg/dL, with the same goal of spending at least 70% of the day within it.
Adjusted Targets for Older Adults
Blood sugar targets loosen as people age, especially when other health conditions or frailty are in the picture. Strict glucose control in older adults increases the risk of dangerous low blood sugar episodes, which can cause falls, confusion, and hospitalization. The trade-off between tight control and safety shifts with age.
For healthy older adults with diabetes, an A1C below 7.5% is a reasonable target, with fasting glucose between 140 and 150 mg/dL. For those with significant health conditions or a life expectancy under 10 years, the A1C target relaxes to 8% or below, with fasting values between 160 and 170 mg/dL. In cases of severe illness or cognitive decline, an A1C up to 8.5% (an average glucose of about 200 mg/dL) may be appropriate, with the primary focus on avoiding both hypoglycemia and extreme highs above 350 mg/dL.
Why Morning Readings Can Run High
If you check your blood sugar first thing in the morning and find it higher than expected, you may be experiencing what’s called the dawn phenomenon. Between roughly 4 a.m. and 8 a.m., your body releases hormones that naturally increase insulin resistance, which can push blood sugar up before you’ve eaten anything. This happens in people with and without diabetes, but it’s more noticeable when your body can’t produce enough insulin to compensate. An unusually high fasting reading doesn’t always mean you ate the wrong thing the night before. It may simply reflect this normal hormonal cycle.
Quick Reference by Situation
- No diabetes, fasting: 70 to 99 mg/dL
- No diabetes, after meals: under 140 mg/dL
- Prediabetes, fasting: 100 to 125 mg/dL
- Diabetes, fasting: 80 to 130 mg/dL (common target)
- Diabetes, CGM target range: 70 to 180 mg/dL for at least 70% of the day
- Gestational diabetes, fasting: 95 mg/dL or lower
- Older adults with diabetes: fasting targets between 140 and 170 mg/dL depending on overall health