Blood Sugar Levels Chart: Understanding mg/dL vs. mmol/L

23 Aug 2025

Blood Sugar Levels Chart: Understanding mg/dL vs. mmol/L Understanding your blood sugar levels is crucial for managing diabetes or pre-diabetes effect...

Blood Sugar Levels Chart: Understanding mg/dL vs. mmol/L

Understanding your blood sugar levels is crucial for managing diabetes or pre-diabetes effectively. This article provides a comprehensive blood sugar levels chart to help you interpret your readings, understand the difference between mg/dL vs. mmol/L, and take appropriate actions based on your results. We'll break down the ideal ranges, explain potential causes for abnormal readings, and offer practical tips for maintaining healthy glucose levels.

Why Blood Sugar Monitoring Matters

Regular blood sugar monitoring is an essential part of diabetes management. It allows you to:

  • Track your body's response to food, exercise, and medication.
  • Identify patterns and trends in your glucose levels.
  • Make informed decisions about your diet and lifestyle.
  • Prevent potentially dangerous complications of diabetes, such as hyperglycemia (high blood sugar) and hypoglycemia (low blood sugar).

Understanding the Units: mg/dL vs. mmol/L

Blood sugar is measured using two primary units:

  • mg/dL (milligrams per deciliter): This is the standard unit used in the United States and several other countries.
  • mmol/L (millimoles per liter): This is the unit used in Canada, Europe, and many other parts of the world.

It's important to know which unit your meter uses and understand how to convert between the two if needed. The conversion formula is:

  • mg/dL = mmol/L x 18
  • mmol/L = mg/dL / 18

For example, a reading of 100 mg/dL is equivalent to 5.5 mmol/L.

Blood Sugar Levels Chart: Target Ranges

The following chart provides a general guideline for blood sugar levels in people with and without diabetes. These are general guidelines and should not replace personalized advice from your healthcare provider. Your target range may vary depending on your individual circumstances and overall health.

Related reading: Decoding Your A1C Levels A Simple Chart And Conversion Guide

Category mg/dL mmol/L
**Fasting (Before Breakfast) - Non-Diabetic** 70-99 mg/dL 3.9-5.5 mmol/L
**Fasting (Before Breakfast) - Diabetic** 80-130 mg/dL 4.4-7.2 mmol/L
**2 Hours After Meal - Non-Diabetic** Less than 140 mg/dL Less than 7.8 mmol/L
**2 Hours After Meal - Diabetic** Less than 180 mg/dL Less than 10.0 mmol/L
**HbA1c (Average over 2-3 Months) - Non-Diabetic** Less than 5.7% N/A
**HbA1c (Average over 2-3 Months) - Diabetic** Less than 7% (Goal set by doctor) N/A

Note: The HbA1c test provides an average of your blood sugar levels over the past 2-3 months. It doesn't use mg/dL or mmol/L as units.

What Causes High Blood Sugar (Hyperglycemia)?

High blood sugar (hyperglycemia) occurs when there is too much glucose in the blood. Common causes include:

  • Dietary factors: Consuming excessive amounts of carbohydrates or sugary foods.
  • Lack of physical activity: Exercise helps lower blood sugar levels.
  • Medication: Insufficient insulin or other diabetes medications.
  • Illness or stress: These conditions can increase blood sugar levels.
  • Dehydration: Staying hydrated helps your kidneys flush out excess sugar.

Symptoms of hyperglycemia include increased thirst, frequent urination, blurred vision, and fatigue. Prolonged hyperglycemia can lead to serious complications, such as nerve damage (neuropathy), kidney damage (nephropathy), and cardiovascular disease.

What Causes Low Blood Sugar (Hypoglycemia)?

Low blood sugar (hypoglycemia) occurs when there is not enough glucose in the blood. Common causes include:

  • Excessive insulin or diabetes medication: Taking too much medication can cause blood sugar to drop too low.
  • Skipping meals or eating too little: Insufficient food intake can lead to hypoglycemia.
  • Intense exercise: Strenuous activity can deplete glucose stores.
  • Alcohol consumption: Alcohol can interfere with the liver's ability to release glucose.

Symptoms of hypoglycemia include shakiness, sweating, dizziness, confusion, and rapid heartbeat. Severe hypoglycemia can lead to loss of consciousness or seizures.

How to Manage Your Blood Sugar Levels

Here are some practical tips for managing your blood sugar levels effectively:

  1. Follow a Healthy Diet: Focus on whole, unprocessed foods, including fruits, vegetables, lean protein, and whole grains. Limit your intake of sugary drinks, processed snacks, and refined carbohydrates.
  2. Engage in Regular Physical Activity: Aim for at least 30 minutes of moderate-intensity exercise most days of the week. This can help improve insulin sensitivity and lower blood sugar levels.
  3. Monitor Your Blood Sugar Regularly: Check your glucose levels as directed by your healthcare provider. Keep a log of your readings to identify patterns and trends.
  4. Take Your Medications as Prescribed: Adhere to your prescribed medication regimen, including insulin or oral diabetes medications. Don't adjust dosages without consulting your doctor.
  5. Stay Hydrated: Drink plenty of water throughout the day to help your kidneys function properly.
  6. Manage Stress: Find healthy ways to cope with stress, such as exercise, meditation, or spending time in nature.
  7. Get Enough Sleep: Aim for 7-8 hours of quality sleep each night to support overall health and well-being.

The Role of Continuous Glucose Monitoring (CGM)

Continuous Glucose Monitors (CGMs) are devices that track blood sugar levels in real-time throughout the day and night. They offer several advantages over traditional finger-prick testing, including:

  • Continuous monitoring: CGMs provide a complete picture of glucose fluctuations.
  • Trend arrows: These indicate the direction and speed of blood sugar changes.
  • Alerts and alarms: CGMs can alert you to high or low blood sugar levels.
  • Data sharing: CGM data can be shared with your healthcare provider for better diabetes management.

Related reading: What To Expect During An Oral Glucose Tolerance Test Ogtt

CGMs can be particularly helpful for people with type 1 diabetes or those who experience frequent blood sugar fluctuations.

When to Seek Medical Attention

It's important to seek medical attention if you experience any of the following:

Related reading: Are Your Blood Sugar Levels Normal A Guide To Testing And Ranges

  • Persistently high or low blood sugar levels that do not respond to treatment.
  • Severe symptoms of hyperglycemia or hypoglycemia, such as loss of consciousness or seizures.
  • Frequent fluctuations in blood sugar levels that are difficult to manage.
  • Signs of diabetes complications, such as nerve pain, vision problems, or kidney problems.

Your healthcare provider can help you develop a personalized diabetes management plan and address any underlying health issues.

Conclusion

Understanding your blood sugar levels and how to interpret them using mg/dL vs. mmol/L is essential for effective diabetes management. By using the provided blood sugar levels chart, adopting healthy lifestyle habits, and working closely with your healthcare team, you can achieve optimal glucose control and prevent potential complications. Remember that this information is for educational purposes only and does not substitute professional medical advice. Always consult with your doctor to determine the best course of treatment for your individual needs.