Blood Sugar Levels Chart

Enter your glucose reading, choose the test type and unit to find out if your level is Normal, Pre-diabetic, or Diabetic.

Test type

Glucose value (mg/dL)

Read this before you act on anything here

This page compares a single glucose or HbA1c number against the diagnostic thresholds published by the American Diabetes Association. That is all it does. It is health information, not medical care, and nothing on it is a diagnosis.

The tool has never examined you. It does not know your age, medical history, medications, pregnancy status, or how the reading was taken, and every one of those changes what a number means. A category label here is a reason to talk to a doctor or pharmacist, never a reason to start, stop, or change a medication or a treatment plan on your own.

If you feel unwell right now, or you have chest pain, difficulty breathing, confusion, fainting, or a reading a clinician told you to treat as an emergency, contact a doctor or go to the nearest emergency department. Do not wait on anything you read here.

Blood Sugar Reference Ranges

Test Type	Normal	Pre-diabetic	Diabetic	Unit
Fasting	< 100	100 – 125	≥ 126	mg/dL
2-Hour OGTT	< 140	140 – 199	≥ 200	mg/dL
HbA1c	< 5.7	5.7 – 6.4	≥ 6.5	%

Conversion: 1 mmol/L = 18.018 mg/dL. HbA1c is always measured in %. The 2-Hour OGTT thresholds (140/200 mg/dL) apply to the standardized oral glucose tolerance test, not a normal meal.

Source

Diagnosis and Classification of Diabetes: Standards of Care in Diabetes—2026 (Section 2). American Diabetes Association, 2026. Diabetes Care 2026;49(Supplement 1):S27-S49. Source of the fasting, 2-hour OGTT and HbA1c cutoffs in the table above. A diagnosis needs a clinician and usually a repeat test, not one reading.

Understanding Blood Sugar Levels

Blood sugar (glucose) is the body's primary source of energy. It comes from the food you eat and is regulated by insulin, a hormone produced by the pancreas. When this regulation breaks down, blood sugar can remain chronically elevated, leading to pre-diabetes or diabetes.

HbA1c explained

Unlike a single glucose reading, HbA1c measures the percentage of hemoglobin in your blood that has glucose attached. Because red blood cells live for about 3 months, HbA1c gives a reliable picture of your average blood sugar over that period. It is the gold standard for monitoring long-term glucose control.

When to test

Fasting: After at least 8 hours of no food or drink (except water). Usually done first thing in the morning.
2-Hour OGTT (Oral Glucose Tolerance Test): Measured 2 hours after drinking a standardized 75 g glucose solution. This is a clinical diagnostic test — thresholds differ from a normal meal.
HbA1c: A blood test done every 3-6 months. Does not require fasting.

Frequently Asked Questions

What is a normal blood sugar level?+

A normal fasting blood sugar is below 100 mg/dL (5.6 mmol/L). After eating, levels below 140 mg/dL (7.8 mmol/L) are considered normal for most adults.

What is HbA1c?+

HbA1c (glycated hemoglobin) measures your average blood sugar over the past 2-3 months. It reflects how well your blood sugar has been controlled and is reported as a percentage. A normal HbA1c is below 5.7%.

How often should I test my blood sugar?+

If you have diabetes, your doctor will advise a testing schedule — often multiple times daily. For pre-diabetic individuals, testing may be recommended every 3-6 months. Healthy adults should get checked at least every 3 years, or more often if risk factors are present.

Can diet affect my blood sugar levels?+

Absolutely. Foods high in refined carbohydrates and sugar cause rapid blood sugar spikes. A diet rich in fiber, lean protein, healthy fats, and whole grains helps maintain stable levels. Regular meal timing and portion control also play an important role.

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