Blood Sugar Levels Chart by Age: Normal, Prediabetes & Diabetes Ranges

Understanding your blood sugar levels by age can help you make sense of glucose test results and recognize when you may need medical advice. However, there is an important point that is often misunderstood: normal blood sugar does not simply increase as you get older. The blood glucose levels used to diagnose prediabetes and diabetes are generally based on the type of test rather than age alone.

What can change with age is the recommended blood sugar target for someone who already has diabetes. Older adults may have different treatment goals depending on their overall health, other medical conditions, risk of low blood sugar, and ability to manage diabetes safely.

In this guide, we explain blood sugar levels by age, fasting and after-meal glucose ranges, normal and prediabetes levels, diabetes diagnostic values, blood sugar targets for people with diabetes, children's and older adults' considerations, pregnancy-related targets, and when high or low blood sugar requires medical attention.

Blood sugar levels and glucose monitoring across different age groups

Blood sugar interpretation depends on the type of test, diabetes status, pregnancy, and individual health factors—not age alone.

Blood Sugar Levels Chart by Age: Quick Overview

The table below gives a practical overview of commonly used blood glucose ranges. It is important to understand that the normal, prediabetes, and diabetes diagnostic ranges are not simply changed according to age. The values depend mainly on the test being performed and whether the person is pregnant.

Group or Situation	Fasting Blood Sugar	Before Meals	After Meals
Non-pregnant adults without diabetes	Below 100 mg/dL is generally normal	Not usually used as a diagnostic category	Depends on the test; 2-hour OGTT below 140 mg/dL is normal
Prediabetes	100–125 mg/dL	Not applicable as a separate diagnostic range	2-hour OGTT: 140–199 mg/dL
Diabetes diagnostic range	126 mg/dL or higher	Not applicable as a separate diagnostic range	Random glucose 200 mg/dL or higher with symptoms may indicate diabetes
Many non-pregnant adults with diabetes	Individual target	80–130 mg/dL is a common target	Below 180 mg/dL about 1–2 hours after the beginning of a meal

These values are general medical guidelines, not personal treatment instructions. A laboratory diagnosis of diabetes generally requires confirmation when the person does not have clear symptoms. Home glucose meter readings are useful for monitoring but should not be used alone to diagnose diabetes. For more information about diabetes testing and diagnosis, see the National Institute of Diabetes and Digestive and Kidney Diseases guide to diabetes tests and diagnosis.

Does Normal Blood Sugar Change With Age?

One of the most common questions is whether older adults are supposed to have higher "normal" blood sugar than younger adults.

The answer is not necessarily.

For diagnosing prediabetes and diabetes in non-pregnant adults, the commonly used fasting blood glucose cutoffs remain:

Normal: 99 mg/dL or below
Prediabetes: 100–125 mg/dL
Diabetes: 126 mg/dL or higher

These diagnostic categories are not automatically raised simply because a person is older.

However, the situation is different for people who already have diabetes. Their individual blood sugar goals may be adjusted according to age, general health, other medical conditions, cognitive function, treatment complexity, and risk of hypoglycemia.

Therefore, it is more accurate to say that diabetes treatment targets may be individualized with age, rather than saying that normal blood sugar naturally becomes higher with age.

Normal Blood Sugar Levels for Children and Teenagers

Children and teenagers can develop diabetes, and blood glucose testing may be recommended when symptoms or risk factors are present.

For children without diabetes, normal blood glucose values are generally interpreted using the same basic principles of glucose testing, although the healthcare professional will consider the child's age, clinical condition, symptoms, and the type of test performed.

Parents should not assume that a child's blood sugar is normal simply because the child is young. Symptoms such as increased thirst, frequent urination, unexplained weight loss, extreme tiredness, or new bed-wetting in a previously toilet-trained child should be discussed with a healthcare professional.

Children with diabetes may have individualized glucose targets. These targets can depend on age, developmental stage, type of diabetes, treatment plan, and risk of hypoglycemia.

Parents and caregivers should follow the glucose targets provided by the child's diabetes care team rather than using a generic online chart to change medication doses.

Normal Blood Sugar Levels for Adults

For non-pregnant adults who do not have diabetes, a fasting plasma glucose level of 99 mg/dL or below is generally considered normal.

A fasting result between 100 and 125 mg/dL falls into the prediabetes range, while a fasting result of 126 mg/dL or higher is within the diabetes range used for diagnosis.

However, a single abnormal result does not always establish a diagnosis. If a person does not have clear symptoms of diabetes, healthcare professionals generally use repeat testing or another accepted diabetes test to confirm the diagnosis.

Other tests may include an A1C test, a 2-hour oral glucose tolerance test, or a random plasma glucose test when appropriate. The CDC's diabetes testing information also explains how different blood glucose tests are used to identify prediabetes and diabetes.

If you want to understand long-term blood sugar control, read our guide to the HbA1c test, normal range, and results.

Blood Sugar Targets for Adults With Diabetes

The blood sugar range used to diagnose diabetes is not the same as the daily target range used by someone who already has diabetes.

For many non-pregnant adults with diabetes, commonly used glucose targets are:

Time of Testing	Common Target for Many Adults With Diabetes
Before a meal	80–130 mg/dL
About 1–2 hours after starting a meal	Below 180 mg/dL
HbA1c for many adults	Below 7%

These are general targets and are not appropriate for every person. Your healthcare professional may recommend different goals based on your age, health status, medications, risk of hypoglycemia, and other individual factors.

For more detailed information about managing blood glucose, you can refer to the American Diabetes Association information on checking blood sugar.

For people living with Type 2 Diabetes, regular monitoring and a personalized treatment plan are important for long-term health.

It is also important to remember that an HbA1c result and a home glucose reading provide different information. HbA1c reflects average blood glucose over approximately three months, while a glucose meter shows your blood sugar at a particular moment.

Fasting Blood Sugar Levels by Age

A fasting blood sugar test measures glucose after you have not eaten for at least 8 hours. Water is generally allowed during the fasting period.

For non-pregnant adults, the commonly used diagnostic categories are:

Fasting Blood Sugar	General Interpretation
Below 100 mg/dL	Normal
100–125 mg/dL	Prediabetes range
126 mg/dL or higher	Diabetes range for diagnosis

These values are used for laboratory diagnosis and do not mean that every home glucose reading in these ranges automatically confirms a medical condition.

For example, a person may occasionally have a higher fasting glucose level because of illness, stress, poor sleep, medication effects, or other factors. Your healthcare professional will interpret the result in context.

Adult checking fasting blood sugar with a glucose meter

A fasting blood glucose test measures blood sugar after a period without food and is commonly used to screen for and diagnose diabetes.

Blood Sugar Levels After Eating

Blood glucose normally rises after eating because carbohydrates are broken down into glucose and absorbed into the bloodstream.

For many non-pregnant adults who already have diabetes, the commonly used target is below 180 mg/dL approximately 1–2 hours after the beginning of a meal.

This target is different from the 2-hour oral glucose tolerance test used for diagnosing diabetes and prediabetes. In an oral glucose tolerance test, the person drinks a measured glucose solution under controlled conditions. A 2-hour value below 140 mg/dL is generally considered normal, 140–199 mg/dL is in the prediabetes range, and 200 mg/dL or higher is in the diabetes range.

Therefore, you should not confuse a routine post-meal home glucose target with the diagnostic result from a formal oral glucose tolerance test.

Food choices, portion sizes, physical activity, medications, stress, sleep, and illness can all influence post-meal glucose levels.

For practical nutrition guidance, our article on healthy eating for weight loss discusses balanced eating habits that can also support better metabolic health.

The Mayo Clinic's information about diabetes management also highlights the importance of monitoring blood sugar, following a balanced eating plan, staying physically active, and working with your healthcare team.

Blood Sugar Levels in Older Adults

Older adults should not assume that high blood sugar is a normal part of aging.

Persistent high blood glucose can still increase the risk of complications involving the heart, blood vessels, kidneys, nerves, eyes, and other organs.

At the same time, diabetes treatment in older adults often requires a more individualized approach. Some older people have multiple medical conditions, take several medications, or have a higher risk of hypoglycemia. For them, a very aggressive glucose-lowering plan may not always be appropriate.

Healthcare professionals may therefore individualize glucose and HbA1c targets according to:

Overall health and life expectancy
Existing diabetes complications
Risk of low blood sugar
Other medical conditions
Cognitive and functional health
Current diabetes medications
Ability to safely manage treatment

The key message is simple: older age does not automatically make a high blood sugar level normal. Instead, the treatment goal may be adjusted to balance the benefits of glucose control with the risks of treatment.

Blood Sugar Levels During Pregnancy

Pregnancy requires special consideration because blood glucose targets can differ from those used for non-pregnant adults.

For many pregnant women with diabetes, commonly recommended targets include:

Timing	Common Pregnancy Target
Fasting	70–95 mg/dL
1 hour after eating	Below 140 mg/dL
2 hours after eating	Below 120 mg/dL

Pregnancy-related glucose targets should always be discussed with the obstetric and diabetes care team because individual recommendations may vary.

Gestational diabetes is diagnosed using specific pregnancy-related testing protocols. A normal blood sugar chart for non-pregnant adults should not be used to interpret pregnancy glucose tests.

The NHS guidance on gestational diabetes provides additional information about blood glucose testing and diabetes during pregnancy.

Prediabetes vs Diabetes: Blood Sugar Diagnostic Chart

Understanding the difference between prediabetes and diabetes is essential because the ranges are close but have different clinical meanings.

Test	Normal	Prediabetes	Diabetes
Fasting plasma glucose	99 mg/dL or below	100–125 mg/dL	126 mg/dL or higher
A1C	Below 5.7%	5.7–6.4%	6.5% or higher
2-hour oral glucose tolerance test	Below 140 mg/dL	140–199 mg/dL	200 mg/dL or higher
Random plasma glucose	Not used for diagnosis	Not used for diagnosis	200 mg/dL or higher with classic symptoms

These diagnostic ranges apply to non-pregnant individuals. Diabetes diagnosis generally requires appropriate confirmation unless symptoms and test results clearly establish the diagnosis.

If your blood sugar results fall into the prediabetes range, it does not necessarily mean that you will develop diabetes. Lifestyle changes, weight management, physical activity, and medical follow-up can help reduce future risk.

You can learn more about sustainable weight management in our guide on how to lose weight and keep it off.

For additional information about preventing or delaying type 2 diabetes, the CDC's National Diabetes Prevention Program resources explain how lifestyle changes can help reduce diabetes risk in people with prediabetes.

Blood sugar diagnostic chart showing normal prediabetes and diabetes ranges

Common diagnostic ranges for fasting glucose and A1C in non-pregnant adults.

What Is Low Blood Sugar?

Low blood sugar, also called hypoglycemia, is generally defined as a blood glucose level below 70 mg/dL for many people with diabetes.

Possible symptoms include:

Shaking or trembling
Sweating
Hunger
Fast heartbeat
Dizziness
Weakness
Confusion
Irritability

Severe hypoglycemia can cause seizures, loss of consciousness, or other serious complications.

If you have diabetes and experience repeated low blood sugar readings, contact your healthcare team. Your medications, food intake, physical activity, alcohol use, or other factors may need to be reviewed.

If a person is unconscious or unable to swallow safely, do not give food or drink by mouth. Emergency medical assistance should be obtained immediately.

The CDC's guidance on treating low blood sugar explains the symptoms of hypoglycemia and the recommended immediate response for people who are able to safely consume carbohydrates.

What Causes High Blood Sugar?

High blood sugar, or hyperglycemia, can occur for many reasons.

Common causes include:

Eating more carbohydrates than planned
Missing or delaying diabetes medication
Insufficient physical activity
Illness or infection
Physical or emotional stress
Certain medications
Insufficient insulin production or action

Long-term high blood sugar can contribute to diabetes complications, which is why regular monitoring and appropriate medical care are important.

People with excess abdominal fat may also have increased insulin resistance. Our article on belly fat and high blood pressure explains how metabolic health and cardiovascular risk can be connected.

Healthy eating physical activity and lifestyle habits for blood sugar control

Balanced nutrition, regular physical activity, healthy weight management, and appropriate medical care can support better blood sugar control.

How to Keep Blood Sugar in a Healthy Range

Healthy blood sugar management is usually based on several habits working together rather than one single food or treatment.

Choose Balanced Meals

Build meals around vegetables, appropriate portions of protein, high-fiber foods, and minimally processed carbohydrates. Limiting added sugars and highly refined carbohydrates can help reduce large glucose spikes.

Stay Physically Active

Regular physical activity can improve insulin sensitivity and support blood glucose management. The type and intensity of exercise should be appropriate for your health and fitness level.

Maintain a Healthy Weight

If you have overweight or obesity, gradual weight loss may improve insulin sensitivity and reduce the risk of type 2 diabetes. Avoid extreme diets that promise rapid results without medical supervision.

Take Prescribed Medicines Correctly

If you have diabetes, take your prescribed medications exactly as directed. Never stop, reduce, or change medication doses based only on a single blood sugar reading without discussing the decision with your healthcare professional.

Monitor Your Blood Sugar When Recommended

Some people with diabetes need regular home glucose monitoring, while others may use continuous glucose monitoring. Your healthcare team can advise you about the most appropriate method and testing schedule.

When Should You See a Doctor?

Speak with a healthcare professional if:

Your fasting blood sugar is repeatedly 100 mg/dL or higher.
Your glucose readings are repeatedly above your personal target.
You have symptoms of diabetes, such as excessive thirst or frequent urination.
You have unexplained weight loss or persistent fatigue.
You experience repeated blood sugar levels below 70 mg/dL.
Your blood sugar is very high and you feel unwell.
You are pregnant and have abnormal glucose readings.
You have diabetes and your usual glucose pattern suddenly changes.

Seek urgent medical attention if you have severe symptoms such as confusion, loss of consciousness, severe dehydration, difficulty breathing, or other signs of a serious medical emergency.

Frequently Asked Questions About Blood Sugar Levels by Age

Does blood sugar naturally increase with age?

Blood sugar may become harder to control as people age because insulin sensitivity and other metabolic factors can change. However, this does not mean that high blood sugar becomes normal or that diagnostic thresholds automatically increase with age.

What is a normal fasting blood sugar level for adults?

For non-pregnant adults, a fasting plasma glucose level of 99 mg/dL or below is generally considered normal. A fasting level of 100–125 mg/dL is in the prediabetes range, while 126 mg/dL or higher is in the diabetes range used for diagnosis.

What is a normal blood sugar level for a 60-year-old?

A 60-year-old does not automatically have a higher normal blood sugar range simply because of age. The same general diagnostic ranges are used for non-pregnant adults, although diabetes treatment targets may be individualized.

What is a normal blood sugar level for a 70-year-old?

The diagnostic ranges for normal glucose, prediabetes, and diabetes do not automatically change at age 70. However, if the person has diabetes, their doctor may personalize treatment targets according to overall health and hypoglycemia risk.

What is a normal blood sugar level for an 80-year-old?

Age alone does not make high blood sugar normal. An 80-year-old without diabetes is generally evaluated using the same diagnostic principles as other non-pregnant adults. For someone with diabetes, treatment goals may be individualized.

Is 120 fasting blood sugar normal?

A fasting blood glucose level of 120 mg/dL is above the normal range and falls within the commonly used prediabetes range. One result should be discussed with a healthcare professional and may require repeat testing or another diabetes test.

Is 150 blood sugar after eating normal?

The answer depends on whether the person has diabetes, when the test was taken, and what type of test was performed. For many adults with diabetes, a glucose level below 180 mg/dL about 1–2 hours after the beginning of a meal is a common target. However, an oral glucose tolerance test uses different diagnostic thresholds.

Is 200 blood sugar dangerous?

A glucose level of 200 mg/dL or higher can be clinically significant, particularly when accompanied by symptoms of diabetes. A random plasma glucose level of 200 mg/dL or higher with classic symptoms can meet the diagnostic criteria for diabetes. If you have very high glucose along with vomiting, severe weakness, confusion, difficulty breathing, or dehydration, seek urgent medical care.

What is the best blood sugar level for someone with diabetes?

There is no single number that is ideal for every person with diabetes. For many non-pregnant adults, common targets are 80–130 mg/dL before meals and below 180 mg/dL about 1–2 hours after starting a meal. Your healthcare professional should determine your individual targets.

Conclusion

A blood sugar levels chart by age can be useful, but it must be interpreted correctly. Normal blood sugar does not automatically become higher simply because a person gets older. For non-pregnant adults, the commonly used diagnostic thresholds for normal blood glucose, prediabetes, and diabetes are based primarily on the type of test rather than age.

What can change with age is the treatment approach for people who already have diabetes. Older adults may need individualized targets that take into account overall health, other medical conditions, medication use, and the risk of hypoglycemia.

For most people, the best approach is to understand the difference between diagnostic ranges and daily treatment targets. If your blood sugar readings are repeatedly outside your recommended range, speak with your healthcare professional rather than trying to diagnose or treat yourself based on an online chart.

Medical Disclaimer

This article is intended for general educational and informational purposes only and does not replace professional medical advice, diagnosis, or treatment. Blood sugar targets can vary depending on age, pregnancy, diabetes type, medications, other medical conditions, and individual health goals. Do not start, stop, or change diabetes medication based solely on information in this article. Always discuss abnormal or repeated blood glucose results with a qualified healthcare professional.

Blood Sugar Levels Chart by Age: Normal, Prediabetes & Diabetes