Blood Sugar Converter

Convert blood glucose levels between mmol/L, mg/dL, and mg% with instant reference range classification.

From

Blood Glucose Reference Ranges

Fasting (8+ hours without food)

Hypoglycemia: < 70 mg/dL (< 3.9 mmol/L)

Normal: 70 - 99 mg/dL (3.9 - 5.5 mmol/L)

Prediabetes: 100 - 125 mg/dL (5.6 - 6.9 mmol/L)

Diabetes: ≥ 126 mg/dL (≥ 7.0 mmol/L)

2 Hours After Eating

Normal: < 140 mg/dL (< 7.8 mmol/L)

Prediabetes: 140 - 199 mg/dL (7.8 - 11.0 mmol/L)

Diabetes: ≥ 200 mg/dL (≥ 11.1 mmol/L)

Quick Reference

mg/dL	mmol/L	Status
50	2.8	Severe Low
54	3.0	Low
70	3.9	Normal
90	5.0	Normal
99	5.5	Normal
100	5.6	Pre
126	7.0	Diabetes
180	10.0	High
200	11.1	High
270	15.0	Very High
360	20.0	Critical

Hypoglycemia (Low Blood Sugar)

Mild: 54 - 69 mg/dL (3.0 - 3.8 mmol/L) — Shakiness, sweating, hunger

Moderate: < 54 mg/dL (< 3.0 mmol/L) — Confusion, difficulty concentrating

Severe: < 50 mg/dL (< 2.8 mmol/L) — Risk of loss of consciousness, seizures

Hyperglycemia (High Blood Sugar)

Mild: 144 - 200 mg/dL (8.0 - 11.0 mmol/L) — May not cause immediate symptoms

Moderate: 200 - 300 mg/dL (11.1 - 16.6 mmol/L) — Frequent urination, increased thirst

Severe: > 300 mg/dL (> 16.7 mmol/L) — Risk of diabetic ketoacidosis (DKA)

Critical: > 500 mg/dL (> 27.8 mmol/L) — Medical emergency

HbA1c (Glycated Hemoglobin)

HbA1c 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)

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

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

How It Works

The conversion uses the molecular weight of glucose (C₆H₁₂O₆ = 180.156 g/mol):

mg/dL = mmol/L × 18.018
mmol/L = mg/dL ÷ 18.018

mmol/L (millimoles per liter) is the SI unit used in the UK, Canada, Australia, and most of Europe. mg/dL (milligrams per deciliter) is used in the United States, Japan, and some other countries. mg% (milligrams percent) is numerically equivalent to mg/dL.

The factor 18.018 comes from: molecular weight of glucose / (10 dL/L × 1000 mg/g) = 180.156 / 10 ≈ 18.018

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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