Blood Sugar Converter

Convert blood glucose (blood sugar) levels between mmol/L and mg/dL units.

From

Blood Glucose Reference Ranges

Fasting Blood Glucose (No food for 8+ hours)

Normal

mmol/L: 3.9 - 5.5

mg/dL: 70 - 99

Prediabetes (Impaired Fasting Glucose)

mmol/L: 5.6 - 6.9

mg/dL: 100 - 125

Diabetes

mmol/L: ≥ 7.0

mg/dL: ≥ 126

Random Blood Glucose (Any time of day)

Normal (2 hours after eating)

mmol/L: < 7.8

mg/dL: < 140

Prediabetes (2 hours after eating)

mmol/L: 7.8 - 11.0

mg/dL: 140 - 199

Diabetes (Random or 2 hours after eating)

mmol/L: ≥ 11.1

mg/dL: ≥ 200

Common Blood Glucose Values

4.0 mmol/L = 72 mg/dL
5.0 mmol/L = 90 mg/dL
5.5 mmol/L = 99 mg/dL
6.0 mmol/L = 108 mg/dL
7.0 mmol/L = 126 mg/dL

8.0 mmol/L = 144 mg/dL
10.0 mmol/L = 180 mg/dL
11.1 mmol/L = 200 mg/dL
15.0 mmol/L = 270 mg/dL
20.0 mmol/L = 360 mg/dL

Hypoglycemia (Low Blood Sugar)

Mild: 3.0 - 3.8 mmol/L (54 - 69 mg/dL) - May cause shakiness, sweating, hunger
Moderate: < 3.0 mmol/L (< 54 mg/dL) - Can cause confusion, difficulty concentrating
Severe: < 2.8 mmol/L (< 50 mg/dL) - Risk of loss of consciousness, seizures

Hyperglycemia (High Blood Sugar)

Mild: 8.0 - 11.0 mmol/L (144 - 200 mg/dL) - May not cause immediate symptoms
Moderate: 11.1 - 16.6 mmol/L (200 - 300 mg/dL) - Frequent urination, increased thirst
Severe: > 16.7 mmol/L (> 300 mg/dL) - Risk of diabetic ketoacidosis (DKA)
Critical: > 27.8 mmol/L (> 500 mg/dL) - Medical emergency

About Blood Glucose Measurement

Blood glucose (blood sugar) refers to the concentration of glucose in the bloodstream. Glucose is the primary source of energy for the body's cells and is tightly regulated by insulin and other hormones.

Units of Measurement

Two main units are used worldwide to measure blood glucose:

mmol/L (millimoles per liter): The SI unit and international standard, used in most countries including UK, Canada, Australia, and Europe. It measures the molar concentration of glucose.
mg/dL (milligrams per deciliter): Used primarily in the United States. It measures the mass concentration of glucose. Also written as mg% (milligrams percent), which is numerically equivalent.

Conversion Formula

The conversion between these units is based on the molecular weight of glucose (C₆H₁₂O₆ = 180.156 g/mol):

mg/dL = mmol/L × 18.0182
mmol/L = mg/dL ÷ 18.0182

The factor 18.0182 comes from: (molecular weight of glucose) / (10 dL/L × 1000 mg/g) = 180.156 / 10 ≈ 18.0182

Note: Some sources use 18 as a simplified conversion factor, but 18.0182 is more accurate.

When to Check Blood Glucose

Fasting: First thing in the morning before eating (8+ hours without food)
Before meals: To guide mealtime insulin dosing
2 hours after meals: To check post-meal glucose response
Before bed: To prevent overnight hypoglycemia
Before and after exercise: To prevent exercise-induced hypoglycemia
When feeling symptoms: Shakiness, sweating, confusion, extreme thirst

HbA1c (Glycated Hemoglobin)

HbA1c is a different measurement that shows average blood glucose over the past 2-3 months:

Normal: < 5.7% (< 39 mmol/mol)
Prediabetes: 5.7% - 6.4% (39 - 47 mmol/mol)
Diabetes: ≥ 6.5% (≥ 48 mmol/mol)
Good control (diabetic): < 7.0% (< 53 mmol/mol)

Factors Affecting Blood Glucose

Food: Carbohydrates raise blood glucose
Exercise: Physical activity lowers blood glucose
Insulin/Medications: Lower blood glucose
Stress: Can raise blood glucose (cortisol release)
Illness: Infections and illness often raise blood glucose
Sleep: Poor sleep can affect glucose regulation
Alcohol: Can cause delayed hypoglycemia

Important Note

Medical Disclaimer: This converter is for informational purposes only. Blood glucose ranges can vary based on individual circumstances, age, pregnancy status, and other medical conditions. Always consult with a healthcare professional for medical advice, diagnosis, or treatment. If you experience severe hypoglycemia or hyperglycemia, seek immediate medical attention.

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