What Are Normal Blood Sugar Levels? A Complete Chart for Adults

18 Sep 2025 By Ramona S. DeJesus, M.D.

What Are Normal Blood Sugar Levels? A Complete Chart for Adults

Understanding normal blood sugar levels is crucial for maintaining overall health and preventing diabetes-related complications. Blood sugar, or glucose, is the primary source of energy for our bodies, and keeping its levels within a healthy range is essential for proper bodily function. This article provides a comprehensive overview of normal blood sugar levels for adults, covering various scenarios such as fasting, before and after meals, and bedtime. We'll also discuss factors that can influence these levels and offer insights into maintaining healthy glucose management.

Why is Monitoring Blood Sugar Important?

Monitoring your blood sugar levels provides valuable insights into how your body is processing glucose. Consistent high blood sugar, known as hyperglycemia, can lead to conditions like prediabetes and type 2 diabetes, increasing the risk of heart disease, kidney problems, nerve damage, and vision loss. Conversely, consistently low blood sugar, or hypoglycemia, can cause symptoms like shakiness, confusion, and even loss of consciousness if severe. Regular monitoring, especially for individuals at risk or diagnosed with diabetes, allows for timely adjustments in diet, exercise, and medication to maintain optimal health.

| Health Condition | Importance of Monitoring | Potential Risks of Uncontrolled Blood Sugar | |-------------------------|------------------------------------------------|---------------------------------------------------| | Prediabetes | Early detection and lifestyle intervention | Progression to Type 2 Diabetes, Heart Disease | | Type 1 Diabetes | Precise insulin management | Ketoacidosis, Hypoglycemia | | Type 2 Diabetes | Medication and lifestyle adjustment | Cardiovascular complications, Nerve damage, Kidney disease | | Gestational Diabetes | Ensuring healthy pregnancy outcomes | Large birth weight, Risk of Type 2 Diabetes for mother and child | Your First Steps In Diabetes Management A Guide For The Newly Diagnosed

Understanding Blood Sugar Levels: Key Terms and Measurements

Before diving into specific numbers, let's define some key terms and measurements used to assess blood sugar levels:

Fasting Blood Sugar (FBS): This is the glucose level measured after at least eight hours of fasting (no food or drink other than water). It is typically measured in the morning before breakfast.
Postprandial Blood Sugar (PPBS): This is the glucose level measured after eating, usually one to two hours after a meal.
HbA1c (Glycated Hemoglobin): This test provides an average of your blood sugar levels over the past two to three months. It measures the percentage of blood sugar attached to hemoglobin, the protein in red blood cells that carries oxygen.
Milligrams per Deciliter (mg/dL): This is the standard unit of measurement for blood sugar in the United States.
Millimoles per Liter (mmol/L): This is the unit of measurement commonly used in many other countries. (To convert mg/dL to mmol/L, divide by 18).

Understanding these terms will help you interpret the blood sugar charts and information presented throughout this article. The Simple Guide To Blood Sugar And Weight Loss For Beginners

Normal Blood Sugar Levels Chart for Adults (Without Diabetes)

For adults without diabetes, maintaining stable blood sugar levels is crucial for overall health and energy levels. Here's a general guideline for normal blood sugar levels throughout the day:

| Time of Day | Blood Sugar Level (mg/dL) | Blood Sugar Level (mmol/L) | |--------------------|---------------------------|----------------------------| | Fasting | 70-99 | 3.9-5.5 | | Before a Meal | 70-99 | 3.9-5.5 | | 1-2 Hours After Meal| Less than 140 | Less than 7.8 | | Bedtime | 100-140 | 5.5-7.8 |

Important Notes:

These values are general guidelines and can vary slightly depending on the individual and the testing method used.
Age can affect blood sugar levels. Older adults may have slightly higher normal ranges.
If you experience symptoms of hyperglycemia (increased thirst, frequent urination, blurred vision) or hypoglycemia (shakiness, sweating, confusion) even within these ranges, consult with your healthcare provider.

Factors Influencing Normal Blood Sugar Levels

Several factors can influence blood sugar levels, even in individuals without diabetes. These include:

Diet: High-carbohydrate foods, especially refined carbohydrates like white bread and sugary drinks, can cause rapid spikes in blood sugar.
Physical Activity: Exercise helps lower blood sugar levels by increasing insulin sensitivity and utilizing glucose for energy.
Stress: Stress hormones, such as cortisol and adrenaline, can increase blood sugar levels.
Sleep: Poor sleep can disrupt hormone balance and lead to insulin resistance, increasing blood sugar levels.
Medications: Certain medications, such as steroids and some diuretics, can raise blood sugar levels.

Blood Sugar Levels Chart for Adults with Diabetes

Managing blood sugar is a daily task for people with diabetes. The target ranges are different from those without diabetes. Here are general guidelines. Individuals should always follow their doctor's specific recommendations.

| Time of Day | Blood Sugar Level (mg/dL) (ADA Target) | Blood Sugar Level (mmol/L) (ADA Target) | Blood Sugar Level (mg/dL) (ACE Target) | Blood Sugar Level (mmol/L) (ACE Target) | |--------------------|--------------------------------------|---------------------------------------|--------------------------------------|---------------------------------------| | Fasting | 80-130 | 4.4-7.2 | Less than 110 | Less than 6.1 | | Before a Meal | 80-130 | 4.4-7.2 | Less than 110 | Less than 6.1 | | 1-2 Hours After Meal| Less than 180 | Less than 10.0 | Less than 140 | Less than 7.8 | | Bedtime | 100-140 | 5.5-7.8 | As advised by physician | As advised by physician |

Key: * ADA: American Diabetes Association * ACE: American Association of Clinical Endocrinology

Important Notes for Individuals with Diabetes:

These are general target ranges. Your healthcare provider may set different targets based on your individual needs, age, overall health, and type of diabetes.
Regular monitoring is essential. Use a blood glucose meter to check your blood sugar levels as directed by your doctor.
Work closely with your healthcare team, including your doctor, certified diabetes educator (CDE), and registered dietitian (RD), to develop a comprehensive diabetes management plan.
Understanding the glycemic index (GI) and glycemic load (GL) of foods can help you make informed dietary choices.
Be aware of the signs and symptoms of both hyperglycemia and hypoglycemia, and know how to treat them.

Factors Influencing Blood Sugar in Diabetes

For people with diabetes, blood sugar is influenced by factors similar to those without diabetes, but they have added considerations.

Insulin or Oral Medications: These help lower blood sugar. Dosage adjustments are often needed based on monitoring results.
Meal Timing and Composition: Balancing carbohydrate intake with insulin or medication is critical.
Exercise: Exercise can significantly lower blood sugar but needs to be planned carefully to avoid hypoglycemia.
Stress: Elevated stress levels can make it harder to manage blood sugar.
Illness: Being sick can raise blood sugar levels due to hormonal changes and decreased activity.

Prediabetes: Understanding Your Risk and Blood Sugar Levels

Prediabetes is a condition where blood sugar levels are higher than normal but not yet high enough to be diagnosed as type 2 diabetes. It is a critical stage where lifestyle changes can significantly reduce the risk of progressing to full-blown diabetes. The Complete Guide To Understanding Your A1C Test Results

Prediabetes Blood Sugar Ranges

| Test | Blood Sugar Level Range (mg/dL) | Blood Sugar Level Range (mmol/L) | |---------------------------|---------------------------------|-----------------------------------| | Fasting Blood Sugar (FBS) | 100-125 | 5.6-6.9 | | HbA1c | 5.7-6.4% | | | 2-Hour OGTT | 140-199 | 7.8-11.0 |

Fasting Blood Sugar (FBS): A fasting blood sugar level between 100 and 125 mg/dL indicates prediabetes.
HbA1c: An HbA1c level between 5.7% and 6.4% indicates prediabetes.
Oral Glucose Tolerance Test (OGTT): A 2-hour blood sugar level between 140 and 199 mg/dL during an OGTT indicates prediabetes. The OGTT involves drinking a sugary liquid and having your blood sugar tested two hours later.

Taking Action if You Have Prediabetes

If you have been diagnosed with prediabetes, it is crucial to take action to prevent or delay the onset of type 2 diabetes. Key strategies include:

Lifestyle Changes: Focus on a healthy diet, regular exercise, and weight loss if you are overweight or obese.
Dietary Adjustments: Reduce your intake of sugary drinks, processed foods, and refined carbohydrates. Increase your consumption of fruits, vegetables, whole grains, and lean protein.
Regular Exercise: Aim for at least 150 minutes of moderate-intensity aerobic exercise per week, such as brisk walking, jogging, or cycling.
Weight Loss: Losing even a small amount of weight (5-7% of your body weight) can significantly improve blood sugar levels and reduce your risk of diabetes.
Medication: In some cases, your doctor may recommend medication, such as metformin, to help lower your blood sugar levels.

Example: A 45-year-old man with a sedentary lifestyle and a family history of diabetes discovers his fasting blood sugar is consistently around 115 mg/dL. He implements changes in his diet, swapping processed snacks for nuts and fruits, and begins walking for 30 minutes most days of the week. After three months, his fasting blood sugar drops to 95 mg/dL, moving him back into the normal range and greatly reducing his risk.

How to Maintain Healthy Blood Sugar Levels

Regardless of whether you have diabetes or not, these are guidelines to maintain healthy blood sugar.

Balanced Diet: Prioritize whole, unprocessed foods, including plenty of fruits, vegetables, lean proteins, and whole grains. Limit sugary drinks, processed snacks, and refined carbohydrates. Pay attention to portion sizes.
Regular Exercise: Aim for at least 150 minutes of moderate-intensity aerobic exercise per week. Include strength training exercises to build muscle mass, which can improve insulin sensitivity.
Hydration: Drink plenty of water throughout the day to help regulate blood sugar levels. Dehydration can cause blood sugar to rise.
Stress Management: Practice relaxation techniques such as meditation, yoga, or deep breathing exercises to manage stress levels. Chronic stress can negatively impact blood sugar control.
Adequate Sleep: Aim for 7-9 hours of quality sleep per night. Lack of sleep can disrupt hormone balance and lead to insulin resistance.
Regular Monitoring: If you have diabetes or prediabetes, regularly monitor your blood sugar levels as directed by your healthcare provider.
Medication Adherence: If you have diabetes, take your medications as prescribed and follow your doctor's instructions carefully.

Practical Tips for Maintaining Stable Blood Sugar

| Strategy | Description | Example | |-------------------------|-----------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------| | Meal Planning | Plan your meals in advance to ensure a balance of carbohydrates, protein, and fat. | Prepare a weekly meal plan with recipes that include whole grains, lean proteins, and plenty of vegetables. | | Portion Control | Use smaller plates and bowls to help control portion sizes. | Instead of filling a large plate, use a smaller plate and only take one serving. | | Snack Wisely | Choose healthy snacks that are low in sugar and high in fiber or protein. | Opt for a handful of almonds, a small apple with peanut butter, or Greek yogurt with berries. | | Read Food Labels | Pay attention to the carbohydrate content, serving size, and ingredients. | Check the nutrition facts label for total carbohydrates, added sugars, and fiber content. | | Limit Sugary Beverages | Avoid sugary drinks like soda, juice, and sweetened tea. | Choose water, unsweetened tea, or sparkling water instead. | | Cook at Home | Cooking your own meals allows you to control the ingredients and portion sizes. | Try cooking simple, healthy recipes at home instead of eating out. |

Example: A 60-year-old who manages her blood sugar by carefully timing her insulin injections with her meals and snacks, as her doctor prescribed. She also does a short walk after dinner to use up extra glucose. On weekends, she prepares all the next week’s lunches ahead of time so she's never tempted to order take-out.

When to See a Doctor

While understanding normal blood sugar ranges is helpful, it is essential to consult with a healthcare professional for personalized advice and guidance. See a doctor if:

You experience frequent or persistent symptoms of hyperglycemia or hypoglycemia.
Your blood sugar levels are consistently outside the target range.
You have risk factors for diabetes, such as family history, obesity, or sedentary lifestyle.
You have been diagnosed with prediabetes.
You have questions or concerns about your blood sugar levels or diabetes management.

Disclaimer: This article provides general information about normal blood sugar levels for adults and should not be considered medical advice. Always consult with a qualified healthcare provider for personalized advice and treatment.