Blood Sugar Levels: Complete Normal Range Chart by Age and Situation

Understanding your blood sugar levels is one of the most important skills you can develop as someone living with — or at risk for — diabetes. Yet the numbers can feel overwhelming: fasting glucose, post-meal targets, A1C percentages, mmol/L versus mg/dL, and different recommendations depending on whether you have Type 1, Type 2, gestational diabetes, or no diabetes at all. This comprehensive guide cuts through the confusion with clear charts, evidence-based targets, and practical guidance you can act on today.

Whether you're a newly diagnosed patient, a parent monitoring a child's glucose, a senior adjusting your targets with your care team, or a caregiver trying to understand what the numbers mean — this is the only reference you need.

Why Blood Sugar Ranges Matter

Blood glucose — the amount of sugar (glucose) circulating in your bloodstream — is your body's primary fuel source. When levels stay consistently too high (hyperglycemia) or drop too low (hypoglycemia), serious complications follow. The American Diabetes Association (ADA) estimates that 37.3 million Americans have diabetes, and another 96 million have prediabetes — most without knowing it. Knowing your numbers is the first line of defense.

Different organizations publish slightly different targets based on their research priorities, so you'll see variation between the ADA, the American Association of Clinical Endocrinology (AACE), and international bodies like the International Diabetes Federation (IDF). We cover all of them below.

Normal Blood Sugar Levels for Adults Without Diabetes

For a person without diabetes, the pancreas automatically keeps blood glucose within a tight range throughout the day. Here are the benchmarks used by most major health organizations:

Sources: ADA Standards of Medical Care in Diabetes 2024; CDC Diabetes Statistics Report 2022

Blood Sugar Targets for People With Diabetes: ADA vs. AACE vs. International

If you've been diagnosed with diabetes, your targets shift. The goal is no longer to mimic perfect physiology, but to prevent complications while minimizing hypoglycemia risk. Here's how the major guidelines compare:

Key takeaway: AACE recommends stricter targets than the ADA for many patients, particularly those at lower hypoglycemia risk. Always discuss your personal targets with your endocrinologist or diabetes care team — the right target for you depends on your age, kidney function, hypoglycemia history, and life expectancy.

Blood Sugar Targets by Diabetes Type

Type 1 Diabetes

People with Type 1 diabetes require insulin for survival and face higher variability in glucose levels. The ADA recommends:

• Pre-meal: 80–130 mg/dL
• Post-meal (1–2 hours): <180 mg/dL
• A1C: <7.0% for most adults; <7.5% for those with hypoglycemia unawareness or frequent low episodes
• Time in Range (CGM): >70% of time in 70–180 mg/dL range

A landmark study — the DCCT (Diabetes Control and Complications Trial) — proved that intensive blood sugar control in Type 1 diabetes reduces the risk of retinopathy by 76%, nephropathy by 50%, and neuropathy by 60%.

Type 2 Diabetes

Targets for Type 2 diabetes are often individualized more broadly, accounting for age, cardiovascular disease history, and medication regimens:

• Pre-meal: 80–130 mg/dL
• Post-meal: <180 mg/dL
• A1C: <7.0% general target; 7.0–8.0% may be acceptable for older adults or those with frequent hypoglycemia

The UKPDS study demonstrated that each 1% reduction in A1C was associated with a 21% decrease in diabetes-related deaths and a 37% reduction in microvascular complications.

Gestational Diabetes

Gestational diabetes requires tighter control to protect both mother and baby. The ADA's targets for gestational diabetes are among the strictest:

• Fasting: <95 mg/dL (5.3 mmol/L)
• 1 hour after meals: <140 mg/dL (7.8 mmol/L)
• 2 hours after meals: <120 mg/dL (6.7 mmol/L)

Poorly controlled gestational diabetes increases the risk of macrosomia (large baby), preeclampsia, and cesarean delivery. It also raises the mother's lifetime risk of developing Type 2 diabetes by approximately 50%, according to research published in Diabetes Care.

Blood Sugar Ranges by Age

Children and Adolescents (Under 18)

Blood sugar management in children, particularly those with Type 1 diabetes, must balance tight control against the serious risks of hypoglycemia on a developing brain. The ADA recommends:

The higher A1C targets in younger children reflect the priority of avoiding dangerous hypoglycemia over achieving perfect glucose control.

Seniors (65 and Older)

Older adults with diabetes often have more relaxed targets due to the heightened risks of falls and cognitive impairment from hypoglycemia, plus shorter time horizons where tight control may provide less benefit. The ADA categorizes seniors into three groups:

• Healthy older adults (few comorbidities): A1C <7.0–7.5%, fasting 80–130 mg/dL
• Complex/intermediate health: A1C <8.0%, fasting 90–150 mg/dL
• Very complex/poor health (multiple chronic conditions): A1C <8.5%, fasting 100–180 mg/dL

Hypoglycemia in seniors is particularly dangerous — a 2019 study in JAMA Internal Medicine found that hypoglycemic episodes were associated with a 2-fold increase in dementia risk in older adults with Type 2 diabetes.

Time in Range (TIR): Targets for CGM Users

Continuous glucose monitors (CGMs) have transformed diabetes management by revealing glucose patterns beyond simple snapshots. The international consensus for Time in Range targets (published in Diabetes Care, 2019) recommends:

Research has shown that a 5% increase in Time in Range corresponds to a clinically meaningful reduction in A1C and is associated with lower rates of diabetic retinopathy and kidney disease progression.

Converting mg/dL to mmol/L (and Back)

The United States uses mg/dL (milligrams per deciliter), while most other countries use mmol/L (millimoles per liter). Converting between them is straightforward:

• mg/dL → mmol/L: Divide by 18 (e.g., 180 mg/dL ÷ 18 = 10.0 mmol/L)
• mmol/L → mg/dL: Multiply by 18 (e.g., 7.0 mmol/L × 18 = 126 mg/dL)

Common reference conversions:

What High Blood Sugar Means (Hyperglycemia)

Hyperglycemia occurs when blood glucose rises above your target range. Short-term symptoms include increased thirst, frequent urination, fatigue, blurred vision, and headaches. Chronically elevated glucose damages blood vessels and nerves throughout the body, leading to:

• Cardiovascular disease — the leading cause of death in people with diabetes
• Diabetic retinopathy — the leading cause of blindness in working-age adults
• Diabetic nephropathy — the leading cause of kidney failure in the US
• Peripheral neuropathy — affecting up to 50% of people with long-standing diabetes
• Diabetic ketoacidosis (DKA) — a life-threatening emergency primarily in Type 1 diabetes

What Low Blood Sugar Means (Hypoglycemia)

Hypoglycemia is defined as blood glucose below 70 mg/dL (3.9 mmol/L). Severe hypoglycemia (<54 mg/dL / 3.0 mmol/L) requires immediate treatment. Symptoms include shakiness, sweating, confusion, rapid heartbeat, and in severe cases, loss of consciousness or seizure.

The Rule of 15 is the standard first response: consume 15 grams of fast-acting carbohydrates (4 glucose tablets, 4 oz juice, or regular soda), wait 15 minutes, and recheck. Repeat if still below 70 mg/dL.

When to Call Your Doctor

Contact your healthcare provider or seek emergency care if:

• Fasting blood sugar is consistently above 130 mg/dL and you have diabetes
• Any reading is above 250 mg/dL and you have Type 1 diabetes (test for ketones)
• Any reading is above 300 mg/dL regardless of diabetes type
• Blood sugar drops below 54 mg/dL or you cannot self-treat a low
• You experience symptoms of DKA: nausea, vomiting, abdominal pain, fruity breath, or confusion
• Your A1C has risen above your personal target at your last lab visit

How to Monitor Your Blood Sugar at Home

Accurate home monitoring is the foundation of diabetes management. A reliable blood glucose meter gives you real-time data to make informed decisions about food, activity, and medication. Testing frequency depends on your treatment plan — people on insulin may test 4–10 times daily, while those managing with diet and oral medication may test less frequently.

For best accuracy: wash hands before testing, use a fresh lancet each time, apply enough blood to fill the test strip completely, and record readings in a logbook or app to share with your care team.

Frequently Asked Questions

What is a normal fasting blood sugar level?

A normal fasting blood sugar — measured after at least 8 hours without food — is 70 to 99 mg/dL (3.9–5.5 mmol/L) for adults without diabetes. A reading of 100–125 mg/dL indicates prediabetes, and 126 mg/dL or higher on two separate tests meets the diagnostic criteria for diabetes, according to the ADA.

What blood sugar level is dangerous?

On the high end, blood sugar above 250 mg/dL in a person with Type 1 diabetes warrants ketone testing; above 300 mg/dL is considered an emergency for most people. On the low end, below 54 mg/dL (3.0 mmol/L) is considered severe hypoglycemia and requires immediate treatment. If a person is unconscious or unable to swallow, call 911 immediately.

What is a normal blood sugar 2 hours after eating?

For people without diabetes, blood sugar should return to below 140 mg/dL (7.8 mmol/L) within 2 hours of a meal. For people with diabetes, the ADA recommends a post-meal target of less than 180 mg/dL (10.0 mmol/L), while AACE recommends a stricter target of less than 140 mg/dL.

What is a good A1C level?

For adults without diabetes, a good A1C is below 5.7%. For most adults with diabetes, the ADA recommends an A1C target of less than 7.0%, which corresponds to an average blood glucose of approximately 154 mg/dL. More or less aggressive targets may be set by your doctor based on your individual situation.

Do normal blood sugar ranges change with age?

Yes — especially for people with diabetes. Children have higher A1C targets to protect against hypoglycemia. Healthy seniors with few complications may aim for the same targets as younger adults, but those with complex health situations may have A1C targets relaxed to 7.5–8.5% to reduce the risk of dangerous hypoglycemia. Always discuss your age-appropriate targets with your diabetes care team.

What is the difference between mg/dL and mmol/L?

These are two different units for measuring blood sugar concentration. The US uses mg/dL (milligrams per deciliter), while most other countries use mmol/L (millimoles per liter). To convert: divide mg/dL by 18 to get mmol/L, or multiply mmol/L by 18 to get mg/dL. For example, 126 mg/dL = 7.0 mmol/L.

What is Time in Range, and why does it matter?

Time in Range (TIR) is a CGM-derived metric that measures the percentage of time your blood glucose stays within a target range — typically 70–180 mg/dL for most adults with diabetes. The international consensus recommends achieving greater than 70% TIR. Research published in Diabetes Care has linked higher TIR with lower rates of diabetic retinopathy, kidney disease, and cardiovascular complications — making it a powerful complement to A1C testing.