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Understand your blood glucose in seconds.

Enter your glucose reading and measurement type to instantly see your classification — Normal, Prediabetes or Diabetes — according to ADA 2024 and WHO diagnostic criteria.

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Blood Glucose Classification
Fasting · 2h post-meal · Random · HbA1c — per ADA 2024 & WHO
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Your reading

mg/dL
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Your result

— mg/dL
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Enter your glucose reading above
Value in mmol/L—
Reference range Fasting—
Classification—
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How it's classified

ADA 2024 diagnostic thresholds explained

This calculator classifies blood glucose levels according to ADA Standards of Medical Care in Diabetes 2024 and WHO diagnostic criteria. For a fasting reading of 95 mg/dL (5.3 mmol/L) the result is Normal. A fasting value of 110 mg/dL (6.1 mmol/L) falls in the Prediabetes range, while 130 mg/dL (7.2 mmol/L) indicates Diabetes. Conversion between mg/dL and mmol/L uses the factor of 18.

Blood glucose classification depends on the type of test and the threshold established by expert bodies. The American Diabetes Association (ADA) and the World Health Organization (WHO) define three main categories — Normal, Prediabetes and Diabetes — each with different cut-points per test type.

mmol/L = mg/dL ÷ 18
mg/dL = mmol/L × 18

Fasting: Normal <100 · Prediabetes 100–125 · Diabetes ≥126 mg/dL
2h post-meal: Normal <140 · Prediabetes 140–199 · Diabetes ≥200 mg/dL
HbA1c: Normal <5.7% · Prediabetes 5.7–6.4% · Diabetes ≥6.5%
  1. 1
    Select the measurement type
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  2. 2
    Convert to mg/dL if needed (÷18 if entering mmol/L)
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  3. 3
    Compare against ADA 2024 thresholds for the chosen test
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  4. 4
    Assign classification and color zone
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Understand the terms

Fasting glucose
Blood glucose measured after at least 8 hours without caloric intake. It reflects baseline glucose regulation and is the most common screening test for diabetes.
Postprandial glucose
Blood glucose measured 2 hours after the start of a meal (or after ingesting 75 g of glucose in a formal oral glucose tolerance test). It assesses how well the body clears glucose after eating.
HbA1c (glycated hemoglobin)
The percentage of hemoglobin molecules with attached glucose. Reflects average blood glucose over the past 2–3 months. Not affected by short-term dietary changes or fasting status.
Prediabetes
A state of higher-than-normal glucose that has not yet reached the diagnostic threshold for diabetes. Strongly associated with progression to type 2 diabetes, but reversible with lifestyle intervention.
Insulin resistance
A condition in which cells respond less effectively to insulin, requiring higher insulin levels to maintain normal glucose. A key driver of prediabetes and type 2 diabetes.
See the full glossary →
Disclaimer: estimation tool for informational and planning purposes, using ADA Standards of Medical Care in Diabetes 2024 and WHO diagnostic criteria. A single abnormal reading is not a diagnosis — diabetes requires confirmation on a repeat test. Symptoms, lab methodology and individual factors may affect results. This tool does not replace assessment by a physician or certified diabetes care professional.
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Frequently asked questions — Blood Glucose

What is a normal fasting blood glucose level?
According to ADA 2024 criteria, a fasting blood glucose below 100 mg/dL (5.6 mmol/L) is considered normal. Values between 100–125 mg/dL (5.6–6.9 mmol/L) indicate prediabetes (impaired fasting glucose), and 126 mg/dL (7.0 mmol/L) or higher on two separate occasions indicates diabetes.
What blood glucose level indicates diabetes?
Diabetes is diagnosed when: fasting glucose ≥126 mg/dL, or 2-hour post-meal glucose ≥200 mg/dL during an oral glucose tolerance test, or HbA1c ≥6.5%, or random glucose ≥200 mg/dL with symptoms of hyperglycemia. A single abnormal test should usually be confirmed on a repeat occasion.
What is the difference between mg/dL and mmol/L?
Both measure blood glucose concentration but in different units. The US uses mg/dL (milligrams per deciliter), while most other countries use mmol/L (millimoles per liter). To convert mg/dL to mmol/L, divide by 18. For example, 100 mg/dL = 5.6 mmol/L.
What is HbA1c and what does it measure?
HbA1c (glycated hemoglobin or hemoglobin A1c) reflects average blood glucose over the past 2–3 months. It measures the percentage of hemoglobin proteins with attached glucose. An HbA1c below 5.7% is normal, 5.7–6.4% indicates prediabetes, and 6.5% or above indicates diabetes per ADA 2024 guidelines.
What is the difference between fasting and postprandial glucose?
Fasting glucose is measured after at least 8 hours without food or drink (except water). Postprandial glucose is measured 2 hours after eating (the start of a meal). Fasting values reflect baseline glucose regulation, while postprandial values show how well your body clears glucose after a meal. Both are used in diabetes diagnosis and monitoring.

📚 Learn more — official sources

📋 Guidelines ADA Standards of Medical Care in Diabetes 2024 — Diagnosis and Classification Official ADA diagnostic criteria for diabetes, prediabetes and hyperglycemia, including fasting, 2h post-meal, random glucose and HbA1c thresholds. See official source → 🏛️ Organization WHO — Definition and Diagnosis of Diabetes Mellitus and Intermediate Hyperglycaemia World Health Organization report defining diagnostic criteria for diabetes and intermediate hyperglycaemia (impaired fasting glucose and impaired glucose tolerance). See official source → 🏛️ Organization NIH NIDDK — Diabetes Tests & Diagnosis National Institute of Diabetes and Digestive and Kidney Diseases guide to blood glucose tests, normal ranges and what results mean for patients and clinicians. See official source → 🏛️ Organization CDC — Diabetes Testing Centers for Disease Control and Prevention resource on blood glucose and HbA1c testing, including how to interpret results and recommended testing intervals. See official source →

About the Blood Glucose Calculator

Blood glucose classification is based on internationally recognized thresholds published by the American Diabetes Association (ADA) Standards of Medical Care in Diabetes 2024 and the World Health Organization (WHO). These criteria are used worldwide to screen, diagnose and monitor diabetes and prediabetes.

This calculator supports four test types — fasting plasma glucose, 2-hour post-meal glucose (oral glucose tolerance test), random glucose and HbA1c — and converts seamlessly between mg/dL and mmol/L. It is intended as an educational and planning aid; any abnormal reading should be discussed with a qualified healthcare provider.

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