Blood sugar, also called blood glucose, is one of the body’s primary sources of energy. Keeping glucose within a healthy range is important because consistently high or low blood sugar can affect overall health and, in people with diabetes, may increase the risk of complications.
But what is a normal blood sugar level? The answer depends on when the blood glucose is measured, whether a person has diabetes, and which test is being used. Fasting blood sugar, blood glucose measured after eating, an oral glucose tolerance test (OGTT), and an A1C test provide different information.
This guide explains normal blood sugar levels, fasting blood sugar levels, blood sugar ranges before and after eating, diabetes and prediabetes thresholds, and when a blood glucose reading may require medical attention.
Medical information: This article is intended for general educational purposes and should not replace diagnosis or treatment from a qualified healthcare professional. Individual blood glucose targets can vary.
What Is a Normal Blood Sugar Level?
For someone without diabetes, a normal fasting plasma glucose level is generally below 100 mg/dL (5.6 mmol/L). A fasting glucose level of 100–125 mg/dL (5.6–6.9 mmol/L) falls within the range used to identify prediabetes, while 126 mg/dL (7.0 mmol/L) or higher is in the diabetes range when confirmed according to appropriate diagnostic testing.
The American Diabetes Association (ADA) also uses an A1C of 5.7%–6.4% as the prediabetes range and 6.5% or higher as a diabetes diagnostic threshold. A 2-hour plasma glucose of 140–199 mg/dL (7.8–11.0 mmol/L) during a 75-g oral glucose tolerance test indicates prediabetes, while 200 mg/dL (11.1 mmol/L) or higher is in the diabetes range.
Importantly, a single home blood glucose reading does not by itself establish a diagnosis of diabetes. When there is no clear evidence of severe hyperglycemia, abnormal diagnostic results generally need confirmation.
Normal Blood Sugar Levels Chart
The following normal blood sugar levels chart summarizes commonly used diagnostic categories for nonpregnant adults.
| Blood glucose test | Normal | Prediabetes | Diabetes* |
|---|---|---|---|
| Fasting plasma glucose | Below 100 mg/dL | 100–125 mg/dL | 126 mg/dL or higher |
| 2-hour glucose during 75-g OGTT | Below 140 mg/dL | 140–199 mg/dL | 200 mg/dL or higher |
| A1C | Below 5.7% | 5.7%–6.4% | 6.5% or higher |
*Diabetes diagnosis generally requires appropriate clinical confirmation when there is not unequivocal hyperglycemia. These are diagnostic criteria, not necessarily individualized day-to-day glucose targets.
This blood sugar levels chart should not be interpreted as a personal diagnosis. Your healthcare professional may recommend additional testing depending on your symptoms, medical history, medications, and risk factors.
What Is a Normal Fasting Blood Sugar Level?
Fasting blood sugar is measured after a person has had no caloric intake for at least eight hours. It is commonly measured in the morning before breakfast.
For nonpregnant adults who do not have diabetes:
- Below 100 mg/dL (5.6 mmol/L): normal fasting glucose
- 100–125 mg/dL (5.6–6.9 mmol/L): prediabetes range
- 126 mg/dL (7.0 mmol/L) or higher: diabetes range when confirmed appropriately
The fasting plasma glucose test is one of the standard tests used to screen for and diagnose diabetes. NIDDK notes that a fasting plasma glucose result of 126 mg/dL or higher should be repeated for confirmation when used for diagnosis.
Fasting Blood Sugar Levels Chart
| Fasting blood glucose | Interpretation |
| Below 100 mg/dL | Normal |
| 100–125 mg/dL | Prediabetes range |
| 126 mg/dL or higher | Diabetes range, requiring confirmation |
Fasting glucose can vary from day to day. Illness, stress, sleep, physical activity, medications, food intake, and other factors can affect glucose levels.
Therefore, if your fasting blood sugar is unexpectedly high or low, discuss the result with a healthcare professional rather than relying on one reading alone.
What Is Normal Blood Sugar After Eating?
Blood glucose normally rises after eating because carbohydrates are broken down into glucose and absorbed into the bloodstream.
Therefore, normal blood sugar after eating is not necessarily identical to fasting glucose. The amount and timing of the rise can vary according to the meal, physical activity, insulin response, medications, and a person’s health.
For diagnostic purposes, a 2-hour glucose value below 140 mg/dL (7.8 mmol/L) during a standardized 75-g oral glucose tolerance test is considered normal. A result of 140–199 mg/dL is in the prediabetes range, and 200 mg/dL or higher is in the diabetes range.
However, it is important to distinguish an OGTT from an ordinary home test taken two hours after a meal. They are not the same test. A typical meal contains a different amount and mixture of carbohydrates, protein, fat, and fiber than the standardized glucose solution used during an OGTT.
Blood Sugar 2 Hours After Eating
For many nonpregnant adults who already have diabetes, the ADA recommends an individualized treatment goal, with a commonly used target of less than 180 mg/dL (10.0 mmol/L) 1–2 hours after the beginning of a meal.
This is a diabetes management target, not a definition of normal glucose in someone without diabetes.
What Is a Normal Blood Sugar Level for Diabetics?
People with diabetes do not necessarily have the same glucose targets as people without diabetes.
For many nonpregnant adults with diabetes, the ADA’s 2026 Standards of Care list the following commonly used goals:
- Before meals: 80–130 mg/dL (4.4–7.2 mmol/L)
- Peak post-meal glucose: below 180 mg/dL (10.0 mmol/L)
- A1C: generally below 7% for many adults
These targets are not universal. The ADA emphasizes that glucose goals should be individualized according to factors such as age, duration of diabetes, other medical conditions, cardiovascular disease, complications, and the risk of hypoglycemia.
Consequently, normal blood sugar for diabetic patients should not be interpreted as one fixed number for everyone.
A person with diabetes should ask their healthcare professional what their personal fasting, pre-meal, post-meal, and A1C targets should be.
Normal Blood Sugar for Adults
The phrase normal blood sugar for adults can refer to several different measurements.
For adults without diabetes, the commonly used diagnostic reference points are:
- Fasting plasma glucose below 100 mg/dL
- 2-hour OGTT glucose below 140 mg/dL
- A1C below 5.7%
For adults with diabetes, treatment targets are different and should be individualized. Many nonpregnant adults with diabetes have a pre-meal target of 80–130 mg/dL and a post-meal target below 180 mg/dL.
This is why asking “what should my blood sugar be?” requires knowing when the test was taken and whether the person has diabetes.
Does Normal Blood Sugar Change With Age?
There is not one simple normal blood sugar range by age that applies to every adult.
The diagnostic thresholds for diabetes and prediabetes are generally based on standardized criteria rather than a simple age-by-age chart. However, glucose management goals may be individualized for older adults, particularly when they have lived with diabetes for many years or have other health conditions.
For example, NIDDK notes that blood glucose goals may differ for adults over 65 who have had diabetes for a long time or who have conditions such as heart disease or frequent episodes of low blood glucose.
Therefore, a blood sugar levels chart by age can be misleading if presented as though every person should have a different fixed glucose range solely because of age.
What Blood Sugar Level Is Considered Diabetes?
According to the ADA’s 2026 diagnostic criteria for nonpregnant individuals, diabetes can be diagnosed using one of several accepted tests:
- A1C: 6.5% or higher
- Fasting plasma glucose: 126 mg/dL (7.0 mmol/L) or higher
- 2-hour plasma glucose during a 75-g OGTT: 200 mg/dL (11.1 mmol/L) or higher
- Random plasma glucose: 200 mg/dL (11.1 mmol/L) or higher when accompanied by classic symptoms of hyperglycemia or a hyperglycemic crisis
In the absence of unequivocal hyperglycemia, the diagnosis generally requires confirmatory testing.
This means a person should not assume they have diabetes based solely on one elevated home glucose reading.
What Blood Sugar Level Is Too High?
There is no single number that defines “too high” for every situation.
For people with diabetes, glucose above an individualized target may indicate hyperglycemia. A reading above 180 mg/dL after a meal is above the commonly used post-meal target for many nonpregnant adults with diabetes. Persistent or substantially elevated readings should be discussed with a healthcare professional.
Very high blood glucose can become an urgent medical concern, particularly when accompanied by symptoms such as:
- Excessive thirst
- Frequent urination
- Nausea or vomiting
- Abdominal pain
- Weakness or unusual fatigue
- Confusion
- Difficulty breathing
People with diabetes should follow the sick-day and high-glucose instructions provided by their healthcare team. Severe symptoms or suspected diabetic ketoacidosis require urgent medical evaluation.
What Blood Sugar Level Is Too Low?
For most people with diabetes, blood glucose below 70 mg/dL (3.9 mmol/L) is considered low blood glucose, or hypoglycemia.
Possible symptoms include:
- Shaking
- Sweating
- Hunger
- Dizziness
- Irritability
- Confusion
- Weakness
- Difficulty concentrating
Severe hypoglycemia can cause seizures, loss of consciousness, or an inability to treat oneself.
The ADA’s 2026 Standards of Care distinguish glucose below 70 mg/dL as level 1 hypoglycemia and below 54 mg/dL (3.0 mmol/L) as level 2 hypoglycemia.
If you frequently experience low blood glucose, speak with your healthcare professional. Diabetes medicines, insulin, meals, exercise, and other factors may all affect glucose levels.
How Is Blood Sugar Measured?
Several tests can be used to evaluate glucose.
1. Fasting Plasma Glucose
This test measures blood glucose after at least eight hours without calories. It is commonly used for diabetes screening and diagnosis.
2. A1C Test
A1C measures glycated hemoglobin and provides an indication of average glucose exposure over approximately the previous three months. It does not require fasting and is commonly used for diabetes screening, diagnosis, and monitoring.
3. Oral Glucose Tolerance Test
During an OGTT, blood glucose is measured after fasting and again after consuming a standardized glucose drink. The 2-hour value is used to identify normal glucose tolerance, prediabetes, or diabetes.
4. Home Blood Glucose Meter
A glucose meter can help people monitor their blood sugar at home. However, home meter readings are not the same as laboratory diagnostic testing. NIDDK specifically notes that meter results should not be used by themselves to diagnose diabetes.
5. Continuous Glucose Monitoring
A continuous glucose monitor (CGM) measures glucose frequently throughout the day and can help some people understand patterns and time spent within a target range. It may be useful for diabetes management, but the ADA notes that there is currently insufficient evidence to use CGM as a screening or diagnostic test for prediabetes or diabetes.
How Can You Maintain Healthy Blood Sugar Levels?
Maintaining healthy glucose levels involves more than simply avoiding sugar.
Helpful habits may include:
Eat balanced meals
Choose meals that include vegetables, high-fiber foods, appropriate sources of protein, and minimally processed carbohydrates. Portion size and overall carbohydrate intake can influence post-meal glucose.
Stay physically active
Regular physical activity can improve insulin sensitivity and help with blood glucose management. Your appropriate activity level depends on your health and medical circumstances.
Take prescribed medicines correctly
If you have diabetes and have been prescribed medication, take it according to your healthcare professional’s instructions. Do not start, stop, or change diabetes medicines based solely on an online blood glucose chart.
Monitor your glucose when recommended
If your healthcare team recommends home monitoring, record your readings along with the time, meals, physical activity, and medicines when appropriate. Patterns can be more informative than a single number.
Attend regular health appointments
Diabetes management may involve A1C testing, blood pressure checks, kidney evaluation, cholesterol testing, eye examinations, and other assessments depending on your individual situation.
Read Blog : How to Take Care of Your Children With Diabetes
Blood Sugar Range Before and After Eating
Understanding timing is essential when interpreting a glucose reading.
A simplified guide is:
| Situation | Common reference/target |
| Fasting, without diabetes | Below 100 mg/dL |
| Fasting, prediabetes range | 100–125 mg/dL |
| Fasting, diabetes range | 126 mg/dL or higher* |
| 2-hour OGTT, normal | Below 140 mg/dL |
| 2-hour OGTT, prediabetes | 140–199 mg/dL |
| 2-hour OGTT, diabetes range | 200 mg/dL or higher* |
| Many adults with diabetes, before meals | 80–130 mg/dL |
| Many adults with diabetes, 1–2 hours after meal begins | Below 180 mg/dL |
*Diagnostic criteria require appropriate clinical interpretation and, in many circumstances, confirmation.
When Should You Talk to a Doctor About Blood Sugar?
Consider speaking with a healthcare professional if:
- Your fasting glucose repeatedly falls in the prediabetes or diabetes range.
- You repeatedly have glucose readings above your recommended target.
- You experience frequent low blood sugar.
- You have symptoms of high blood glucose.
- You have symptoms of hypoglycemia.
- You have been diagnosed with diabetes and your readings are consistently outside your individualized targets.
- You are unsure how to interpret your blood glucose results.
Seek urgent medical attention for severe symptoms such as confusion, loss of consciousness, seizures, severe vomiting, or difficulty breathing.
Frequently Asked Questions About Normal Blood Sugar Levels
1. What is a normal blood sugar level?
For a nonpregnant adult without diabetes, a fasting plasma glucose below 100 mg/dL (5.6 mmol/L) is generally considered normal. A 2-hour glucose below 140 mg/dL during a standardized 75-g OGTT is also within the normal range.
2. What is a normal fasting blood sugar level?
A normal fasting blood sugar level is generally below 100 mg/dL (5.6 mmol/L). Fasting means having no caloric intake for at least eight hours before the laboratory test.
3. What should blood sugar be 2 hours after eating?
There is no single universal “normal” value for an ordinary meal. For diagnostic purposes, a 2-hour glucose below 140 mg/dL is normal during a standardized 75-g OGTT. For many adults with diabetes, the ADA recommends a post-meal treatment goal below 180 mg/dL, measured 1–2 hours after the beginning of the meal.
4. What blood sugar level is considered diabetes?
Diabetes can be diagnosed using an A1C of 6.5% or higher, fasting plasma glucose of 126 mg/dL or higher, a 2-hour OGTT glucose of 200 mg/dL or higher, or a random plasma glucose of 200 mg/dL or higher when accompanied by classic symptoms or hyperglycemic crisis. Appropriate confirmation is generally required when severe hyperglycemia is not unequivocal.
5. What blood sugar level is too high?
For people with diabetes, a reading above their individualized target may be considered high. For many nonpregnant adults with diabetes, the commonly recommended post-meal target is below 180 mg/dL. Repeated or substantially elevated readings should be discussed with a healthcare professional.
6. What blood sugar level is too low?
For most people with diabetes, blood glucose below 70 mg/dL (3.9 mmol/L) is considered low. Glucose below 54 mg/dL (3.0 mmol/L) represents a more serious level of hypoglycemia.
7. What is a normal blood sugar level for diabetics?
There is no single normal value for everyone with diabetes. For many nonpregnant adults, commonly used ADA targets are 80–130 mg/dL before meals and below 180 mg/dL 1–2 hours after the beginning of a meal. Individual targets may be higher or lower depending on health circumstances.
8. Does normal blood sugar change with age?
The diagnostic thresholds for diabetes and prediabetes are not simply changed according to adult age. However, glucose targets for people who already have diabetes may be individualized, particularly in older adults and people with other health conditions or a higher risk of hypoglycemia.
Key Takeaways
Normal blood sugar levels depend on when and how glucose is measured. For nonpregnant adults without diabetes, fasting glucose below 100 mg/dL is generally considered normal, while 100–125 mg/dL is in the prediabetes range and 126 mg/dL or higher is in the diabetes range when appropriately confirmed.
A standardized 2-hour OGTT result below 140 mg/dL is considered normal. For many adults with diabetes, common treatment targets are 80–130 mg/dL before meals and below 180 mg/dL 1–2 hours after the beginning of a meal.
Most importantly, blood glucose targets should be individualized. A blood sugar chart can help you understand general ranges, but it cannot diagnose diabetes or determine the right treatment for an individual.
If your glucose readings are repeatedly outside the expected range, discuss them with a qualified healthcare professional. Do not change prescribed diabetes medication or insulin based solely on information from an online article.
Medical Review and Sources
This article should be medically reviewed by a qualified physician, endocrinologist, or other appropriately credentialed healthcare professional before publication. For YMYL/E-E-A-T compliance, the page should display the reviewer’s credentials, review date, author information, and links to authoritative medical references.
Primary medical references:
- American Diabetes Association, Standards of Care in Diabetes—2026: Diagnosis and Classification of Diabetes.
- American Diabetes Association, Standards of Care in Diabetes—2026: Glycemic Goals, Hypoglycemia, and Hyperglycemic Crises.
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Diabetes & Prediabetes Tests.
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Managing Diabetes.
- Diagnosis and Classification of Diabetes: Standards of Care in Diabetes-2026