Normal Blood Sugar Levels In Adults with Diabetes

Medically Reviewed on 3/8/2022

Normal Blood sugar levels in adults with type 1 or type 2 diabetes

Target blood sugar levels in adults with diabetes
Chart Showing Target Blood Sugar Levels for Diabetes

Diabetes is defined as a disease in which the body has an impaired ability to either produce or respond to the hormone insulin. People with type 1 diabetes have a pancreas that does not make insulin. People with type 2 diabetes have cells in the body that are resistant to insulin or have a pancreas that slows or stops producing adequate insulin levels (blood glucose). Both types of diabetes can result in abnormal glucose levels.

Normal blood levels may range slightly depending on what blood tests are used, but the variances are small. In addition, the “normal” ranges for non-diabetics are not the same for people with diabetes; it is generally accepted that target blood sugar measurements for people with diabetes will be slightly higher than those without diabetes.

  • A person with normal blood sugar levels has a normal glucose range of 72-99 mg/dL while fasting and up to 140 mg/dL about 2 hours after eating.
  • People with diabetes who have well-controlled glucose levels with medications have a different target glucose range. These people may have a fasting range of about 100 mg/dL or less and 180 mg/dL about 2 hours after eating.
  • If a person’s diabetes is not well controlled, the person may have much higher glucose ranges (for example, 200 -400 mg/dL; however, some people with diabetes have blood sugar levels that are much higher).

What are normal blood sugar levels before and after eating?

The normal ranges for blood sugar levels in adults who do not have diabetes while fasting are 72-99 mg/dL. These ranges may increase to 80-130 mg/dL for those being treated for diabetes. 

According to the American Diabetes Association, people with diabetes should have

  • blood sugar levels of 80-130 mg/dL before eating a meal (fasting), and
  • less than 180 mg/dL about 1-2 hours after eating a meal

High blood sugar ranges for people who don’t have diabetes begin at 140 mg/dL, while those being treated for diabetes have a high range beginning at 180 mg/dL.

Are high levels of blood sugar dangerous?

Yes, high blood sugar levels can be dangerous. Although high blood sugar levels commonly produce symptoms of excessive urination, excessive thirst and hunger, and weight loss, over time these high blood sugar levels can cause

  • lower-extremity paresthesias (“pins and needles” sensations) and/or loss of feeling,
  • blurry vision,
  • a higher risk for infections 
  • kidney and eye damage,
  • a higher risk of heart attack,
  • a higher risk of stroke.

Very high blood sugar levels (for example, 1000 or more mg/dL) can cause diabetic ketoacidosis, which can lead to loss of consciousness and is life-threatening. The treatment for excessively high blood sugar involves IV fluids and insulin.


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Are low blood sugar levels dangerous?

Yes, low blood sugar symptoms can cause problems such as

Low blood sugar levels begin at 70 mg/dL or less.

  • People with diabetes who take too much medication (insulin) or take their usual amount but then eat less or exercise more than usual can develop hypoglycemia. Although much rarer, hypoglycemia may develop in some people without diabetes when they take someone else’s medication, have excessive alcohol consumption, or have hepatitis or a rare tumor of the pancreas (insulinoma).
  • The treatment for hypoglycemia is oral glucose intake (15.0 grams of sugar, for example, 1 tablespoon of sugar, honey, corn syrup, or IV fluids containing glucose. Rechecking your blood sugar levels in about 15 minutes after the treatment is advised.

What can you do to manage your blood glucose levels?

  • Diet modification is a major step in your management of diabetes.
  • Don't eat foods high in carbohydrates and sugar such as buttered potatoes, fatty foods, candy, and sugary desserts like cake with frosting.
  • Use a blood sugar logbook or app that records the date, time, and values to help you manage your type 1 diabetes or type 2 diabetes, and
  • use a blood glucose home test kit to get glucose test results.
  • Additionally, log any change in symptoms over time. The logbook will enable you and your doctor to modify treatments (for example, the amount of insulin to take) and actions to obtain the best management of your diabetes.
Medically Reviewed on 3/8/2022
Checking Your Blood Glucose. American Diabetes Association. Updated Oct 09, 2018.

Khardori, R, MD, et al. Type 1 Diabetes Mellitus. Medscape. Updated: Oct 22, 2018.

Khardori, R, MD, et al. Type 1 Diabetes Mellitus. Medscape. Updated: Apr 05, 2018.