Blood Sugar Level Chart: What’s Normal, Low, and H
What are normal blood sugar levels in adults with type 1 or type 2 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 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 for 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 blood sugar 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 symptoms commonly include excessive urination, excessive thirst, hunger, weight loss, fatigue, and headaches, over time these high blood sugar levels can cause the following:
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.
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.
What can you do to manage your blood glucose levels?
You can manage your blood glucose levels with the following tips:
Frequently asked questions
Health News
Medically Reviewed on 1/24/2025
References
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https://www.diabetes.org/living-with-diabetes/treatment-and-care/blood-glucose-control/checking-your-blood-glucose.html
Khardori, R, MD, et al. Type 1 Diabetes Mellitus. Medscape. Updated: Oct 22, 2018.
https://emedicine.medscape.com/article/117739-overview
Khardori, R, MD, et al. Type 1 Diabetes Mellitus. Medscape. Updated: Apr 05, 2018.
https://emedicine.medscape.com/article/117739-overview
Low Blood Glucose (Hypoglycemia). American Diabetes Association. Accessed December 27, 2024. https://diabetes.org/living-with-diabetes/hypoglycemia-low-blood-glucose
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Diabetes management: How lifestyle and daily routine affect blood sugar. Mayo Clinic. Accessed December 27, 2024. https://www.mayoclinic.org/diseases-conditions/diabetes/in-depth/diabetes-management/art-20047963
Diabetes. NIH. Accessed December 27, 2024. https://www.niddk.nih.gov/health-information/diabetes