Written by: Dr. Albana Greca Sejdini, MD, MMedSc
Medically reviewed by: Dr. Ruden Cakoni, MD, Endocrinologist
Last medically reviewed: July 2026
Normal blood sugar levels are not one single number. They depend on when you test, whether you have eaten, whether you have diabetes, and what treatment you use.
As I explain to my patients, a blood sugar chart is useful only when you understand the context of the reading. A fasting result, a reading two hours after a meal, and an A1C result do not mean the same thing. This page will help you read your numbers more safely, but it should not replace personal medical advice from your own doctor.
For many nonpregnant adults with diabetes, common blood sugar targets are around 80–130 mg/dL before meals and less than 180 mg/dL about 2 hours after the start of a meal. These values are general targets, not personal medical instructions.
Your safe target may be different if you are pregnant, elderly, a child or teenager, using insulin, having frequent low blood sugar, or living with kidney, heart, or other serious health conditions.
This chart gives general blood sugar ranges in both mg/dL and mmol/L. Always interpret your result together with the time of testing, your symptoms, your medications, and your personal diabetes plan.
| Test or situation | General range in mg/dL | General range in mmol/L | What it may mean |
|---|---|---|---|
| Fasting blood sugar | 99 or below | 5.5 or below | Usually considered normal |
| Fasting blood sugar | 100–125 | 5.6–6.9 | Prediabetes range |
| Fasting blood sugar | 126 or higher | 7.0 or higher | Diabetes range if confirmed by repeat testing |
| 2-hour oral glucose tolerance test | 140 or below | 7.8 or below | Usually considered normal |
| 2-hour oral glucose tolerance test | 140–199 | 7.8–11.0 | Prediabetes range |
| 2-hour oral glucose tolerance test | 200 or higher | 11.1 or higher | Diabetes range if confirmed |
| Before meals in many adults with diabetes | 80–130 | 4.4–7.2 | Common treatment target, if safe for the patient |
| About 2 hours after meals in many adults with diabetes | Less than 180 | Less than 10.0 | Common treatment target, if safe for the patient |
| Low blood sugar alert | Below 70 | Below 3.9 | Hypoglycemia; treat promptly according to your care plan |
These are general targets, not personal instructions. Your ideal range may be different if you are pregnant; older; a child or teenager; using insulin; having frequent low blood sugar; or living with heart, kidney, liver, or other medical conditions.
A normal blood sugar level chart is a simple guide that helps you compare your glucose readings with common medical ranges.
As I explain to my patients, one number alone does not tell the whole story. Blood sugar changes during the day. It may be lower before meals, higher after eating, and affected by sleep, stress, illness, exercise, medication timing, and the type of food you eat.
That is why your chart should show when the test was done, not only the number.
These values are commonly used by healthcare professionals when screening for prediabetes and diabetes. A diagnosis is usually confirmed with repeat testing or additional evaluation by a doctor, especially if results are borderline or symptoms are present.
| Test | Normal range | Prediabetes range | Diabetes range |
|---|---|---|---|
| Fasting blood sugar | 99 mg/dL or below | 100–125 mg/dL | 126 mg/dL or above |
| Fasting blood sugar | 5.5 mmol/L or below | 5.6–6.9 mmol/L | 7.0 mmol/L or above |
| 2-hour oral glucose tolerance test | 140 mg/dL or below | 140–199 mg/dL | 200 mg/dL or above |
| 2-hour oral glucose tolerance test | 7.8 mmol/L or below | 7.8–11.0 mmol/L | 11.1 mmol/L or above |
| A1C | Below 5.7% | 5.7–6.4% | 6.5% or above |
For many nonpregnant adults with diabetes, doctors often use the following general targets.
| Time of day | Common diabetes target | mmol/L |
|---|---|---|
| Before breakfast / fasting | 80–130 mg/dL | 4.4–7.2 mmol/L |
| Before meals | 80–130 mg/dL | 4.4–7.2 mmol/L |
| 1–2 hours after starting a meal | Less than 180 mg/dL | Less than 10.0 mmol/L |
| Bedtime | Individualized | Individualized |
| A1C | Often less than 7%, if safe | — |
These are general targets for many nonpregnant adults with diabetes. Your personal goal may be different depending on your age, pregnancy status, medications, risk of low blood sugar, and other health conditions. Always follow the advice of your doctor.
Please remember lower is not always better. If a patient has frequent low blood sugar, advanced age, kidney disease, heart disease, or difficulty recognizing hypoglycemia, the doctor may choose a safer, higher target.
Blood sugar numbers are easier to understand when you look at the time of testing. A fasting reading, a before-meal reading, an after-meal reading, or a bedtime reading can each tell a different part of the story. The table below explains what each testing time may show and why it can help you and your doctor better understand your daily blood sugar pattern.
Blood sugar readings can mean different things depending on when you test. The table below explains what each testing time may show and why it matters.
| Time of test | What the number may show | Why it matters |
|---|---|---|
| Fasting / morning | Your baseline glucose before food | Useful for diabetes screening and morning control |
| Before meals | How well your glucose returns before eating again | Helps review medication and meal timing |
| 1–2 hours after meals | How your body responds to food | Helpful for understanding carbohydrates and meal portions |
| Bedtime | Overnight safety | Important for people using insulin or medicines that can cause lows |
| During symptoms | Possible high or low blood sugar | Helps you act quickly and safely |
Source: www.all-about-beating-diabetes.com
For many people with diabetes, low blood sugar, also called "hypoglycemia," is usually defined as a blood glucose reading below 70 mg/dL, or below 3.9 mmol/L. At this level, the body may not have enough glucose available for normal energy and brain function.
Symptoms may include:
Severe low blood sugar can cause seizure, loss of consciousness, or coma. This is an emergency.
If your doctor has taught you the 15–15 rule, follow it: take 15 grams of fast-acting carbohydrate, wait 15 minutes, and recheck your blood sugar. If you are unconscious, confused, unable to swallow, or not improving, someone should call emergency help.
Blood sugar may be too high if your readings are repeatedly above your target range.
Call your doctor if:
Seek urgent medical help if high blood sugar happens with vomiting, deep or difficult breathing, confusion, severe weakness, dehydration, or signs of diabetic ketoacidosis.
Many patients feel worried when one number is high. I usually remind them: do not judge your health from one isolated reading. Look for patterns.
Common reasons for high or low blood sugar include:
The table below shows common blood sugar values in both mg/dL and mmol/L, with a short explanation of what each number may mean.
| mg/dL | mmol/L | What it may mean |
|---|---|---|
| 54 | 3.0 | Very low; needs urgent attention |
| 70 | 3.9 | Low blood sugar alert for many people with diabetes |
| 80 | 4.4 | Lower end of common before-meal diabetes target |
| 99 | 5.5 | Upper normal fasting range for people without diabetes |
| 100 | 5.6 | Beginning of prediabetes fasting range |
| 126 | 7.0 | Diabetes range if confirmed by lab testing |
| 140 | 7.8 | Upper normal 2-hour glucose tolerance value |
| 180 | 10.0 | Common after-meal target limit for many adults with diabetes |
| 200 | 11.1 | Diabetes range for 2-hour glucose tolerance test if confirmed |
| 250 | 13.9 | High reading; follow your sick-day or doctor plan |
Source: www.all-about-beating-diabetes.com
A1C is different from a finger-stick glucose test.
A finger-stick glucose test shows your blood sugar at one moment.
A1C estimates your average blood sugar over the last 2 to 3 months.
The A1C test gives an estimate of your average blood sugar over the last 2 to 3 months. The table below shows how common A1C results may compare with estimated average glucose levels.
| A1C | Estimated average glucose |
|---|---|
| 6% | 126 mg/dL |
| 7% | 154 mg/dL |
| 8% | 183 mg/dL |
| 9% | 212 mg/dL |
| 10% | 240 mg/dL |
Source: www.all-about-beating-diabetes.com
A1C is useful, but it does not show daily highs and lows. Some people may have a good A1C but still have frequent glucose spikes or low blood sugar. That is why home monitoring or continuous glucose monitoring may be important for some patients.
Your doctor may personalize your targets if you are:
This is why I do not want my patients to copy a chart blindly. A chart is a guide. Your treatment plan must be personal.
When you write down your readings, include:
Bring this record to your doctor. It helps us see patterns and make safer decisions.
Small daily steps can make a real difference:
Call your doctor if you notice repeated readings outside your target range, especially if the pattern continues for several days.
Call sooner if you have:
What is a normal fasting blood sugar?
For people without diabetes, a normal fasting blood sugar is usually 99 mg/dL or below. For many adults living with diabetes, a commonly used fasting blood sugar target is 80–130 mg/dL. However, the best target is not the same for everyone. Your doctor may recommend a different goal based on your age, medications, risk of low blood sugar, pregnancy status, and overall health.
What should blood sugar be 2 hours after eating?
For people without diabetes, a 2-hour glucose tolerance value is usually 140 mg/dL or below. For many adults with diabetes, a common after-meal target is less than 180 mg/dL.
Is 135 mg/dL high for blood sugar?
It depends on when you checked it. A reading of 135 mg/dL may be acceptable after a meal, but it may be high if it is a fasting reading. Always interpret the number together with timing, symptoms, and your personal plan.
Is 180 mg/dL after eating dangerous?
For many adults with diabetes, less than 180 mg/dL 1–2 hours after a meal is a common target. One reading slightly above this does not always mean danger, but repeated high after-meal readings should be discussed with your doctor.
What is considered low blood sugar?
For many people with diabetes, low blood sugar is below 70 mg/dL, or below 3.9 mmol/L. If you have symptoms or use insulin, follow the low blood sugar plan given by your doctor.
Can I have normal fasting blood sugar but still have diabetes?
Yes. Some people have normal fasting readings but high after-meal readings or an elevated A1C. Your doctor may use fasting glucose, A1C, glucose tolerance testing, and your symptoms to understand the full picture.
Why is my fasting blood sugar high in the morning?
Morning blood sugar may rise because of the dawn phenomenon, late evening snacks, poor sleep, stress, illness, insulin resistance, or medication timing. If this happens repeatedly, show your readings to your doctor.
Should I use mg/dL or mmol/L?
Both are correct units. The United States commonly uses mg/dL. Many other countries use mmol/L. To convert mg/dL to mmol/L, divide by 18.