Blood Sugar Conversion Chart & Calculator: Easy mg/dL to mmol/L Guide (With Tools & Tips)

If you’ve ever looked at a blood sugar reading and thought, “What do these numbers actually mean?”—you’re not alone. Whether you're managing diabetes, tracking your blood sugar for weight loss or longevity, or just curious about how food affects your body, knowing how to understand and convert blood sugar levels is incredibly important.

The challenge? Blood sugar is measured differently depending on where you live. In the United States, it’s typically measured in mg/dL (milligrams per deciliter). In most other parts of the world, the unit used is mmol/L (millimoles per liter). So, when you see glucose numbers in a different format, it can be confusing unless you know how to convert them.

In this guide, you’ll get:

• A simple explanation of the two main blood sugar units
• Easy formulas for converting between mg/dL and mmol/L
• A helpful conversion chart
• A user-friendly calculator
• Insights into healthy blood sugar ranges
• And tips on keeping your levels in check

Let’s dive into everything you need to know.

What’s the Difference Between mg/dL and mmol/L?

Let’s start by breaking it down.

mg/dL stands for milligrams per deciliter. It tells you how many milligrams of glucose are in one-tenth of a liter of blood. This unit is mostly used in the United States and a few other countries.

mmol/L stands for millimoles per liter. It measures how many millimoles of glucose are in a liter of blood. This unit is used by most of the rest of the world, including Canada, the UK, Australia, and much of Europe.

To make sense of it: both units measure the same thing (glucose in your blood), but they use different scales. It’s kind of like converting between miles and kilometers—the concept is the same, but the numbers look different.

How to Convert Blood Sugar Units

Luckily, converting between mg/dL and mmol/L is pretty simple once you know the formulas.

To convert mg/dL to mmol/L: divide the number by 18. To convert mmol/L to mg/dL: multiply the number by 18.

Let’s go through some examples:

• If your blood sugar is 90 mg/dL, then 90 ÷ 18 = 5.0 mmol/L
• If your blood sugar is 7.8 mmol/L, then 7.8 × 18 = 140 mg/dL

These formulas work in both directions, so it’s easy to convert no matter what unit your device or doctor uses.

Blood Sugar Conversion Chart (mg/dL to mmol/L)

Here’s a simple chart to help you quickly convert blood sugar readings between mg/dL and mmol/L:

Keep this chart handy if you need to interpret readings from a different unit than you’re used to.

Blood Sugar Conversion Calculator

If you want to avoid mental math or keep things quick and accurate, a calculator can help. Here’s how to use a simple version:

1. Enter your blood sugar number.
2. Choose your current unit (mg/dL or mmol/L).
3. The calculator instantly gives you the converted value.

For example:

• You input 100 mg/dL → output = 5.6 mmol/L
• You input 6.5 mmol/L → output = 117 mg/dL

While we can’t show an interactive calculator right here, many websites offer free online versions, or you can create your own with a simple spreadsheet using the formulas above.

What’s a Healthy Blood Sugar Range?

Understanding your numbers is only half the battle. The other half is knowing what they mean for your health. Here are the general ranges:

Fasting Blood Sugar (no food for 8+ hours):

• 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 or higher (7.0+ mmol/L)

Post-Meal (1–2 hours after eating):

• Normal: Under 140 mg/dL (7.8 mmol/L)
• Diabetes: Over 180 mg/dL (10.0 mmol/L)

A1c Levels (3-month average):

• Normal: Below 5.7%
• Prediabetes: 5.7–6.4%
• Diabetes: 6.5% or above

These ranges are based on guidelines from trusted sources like the American Diabetes Association and the World Health Organization.

Why Blood Sugar Conversion Matters

Let’s say you’re traveling and your glucose meter shows mmol/L, but you’re used to mg/dL. Or maybe you’re reading an article or research paper from another country and the values don’t match what your doctor uses.

Knowing how to convert units helps you:

• Understand medical advice
• Compare international research
• Communicate clearly with healthcare professionals
• Monitor your health accurately, especially if using CGMs or tracking devices from other regions

This knowledge is also empowering. It helps you take charge of your health and avoid feeling overwhelmed by numbers and jargon.

How to Keep Blood Sugar in a Healthy Range

Even if you don’t have diabetes, keeping your blood sugar steady can improve your energy, mood, sleep, weight, and overall long-term health. So how do you do it?

Start with these basics:

Eat Balanced Meals Include protein, fiber, and healthy fats with every meal. These slow down sugar absorption and prevent spikes.

Move Regularly Even a 10-minute walk after meals can help regulate your glucose response.

Try Intermittent Fasting Some people find that eating within a shorter window during the day helps stabilize their blood sugar levels. Always consult your doctor first.

Limit Added Sugars and Refined Carbs Processed snacks, soda, and baked goods can lead to quick spikes and crashes.

Track Your Levels Use a glucose monitor or CGM to understand how your body reacts to different foods and routines.

Manage Stress and Sleep Both stress and poor sleep can raise your blood sugar. Prioritize relaxation, deep breathing, and quality rest.

High-Intent FAQs on Blood Sugar Conversion and Monitoring

1. Can I change the units displayed on my blood glucose meter?

It depends on the model of your blood glucose meter. Some meters allow you to switch between mg/dL and mmol/L, while others are fixed to a single unit. To find out if your device supports unit conversion, consult the user manual or contact the manufacturer's customer support.

2. Why do different countries use different units for blood sugar measurement?

The use of mg/dL and mmol/L stems from historical and regional preferences. The United States commonly uses mg/dL (milligrams per deciliter), while most other countries, including Canada, the UK, and Australia, use mmol/L (millimoles per liter). Both units measure the concentration of glucose in the blood but express it differently.

3. How do I convert my A1C value to an average blood glucose level?

The A1C test reflects your average blood glucose over the past 2-3 months. To estimate your average glucose level from your A1C percentage, you can use the following formula:

Estimated Average Glucose (mg/dL) = (A1C × 28.7) - 46.7

For example, an A1C of 7% corresponds to an estimated average glucose of approximately 154 mg/dL.

4. Is there a difference between capillary and venous blood glucose readings?

Yes, there can be slight differences. Capillary blood glucose readings, obtained from fingerstick tests, may differ slightly from venous blood samples analyzed in a laboratory. Factors such as blood flow and sample handling can contribute to these variations. However, for most monitoring purposes, capillary readings are sufficiently accurate.

5. What is the significance of the conversion factor 18 when converting blood sugar units?

The factor 18 is used to convert between mg/dL and mmol/L because it relates to the molecular weight of glucose. Specifically, 1 mmol/L of glucose is equivalent to 18 mg/dL. This conversion factor simplifies the process of translating blood sugar values between the two units.

6. Are there any tools available to help convert blood sugar units?

Yes, several online calculators and conversion charts are available to assist with converting blood sugar values between mg/dL and mmol/L.

7. How do I interpret blood sugar readings in different units?

Understanding blood sugar readings requires familiarity with the units used:

• mg/dL (milligrams per deciliter): Commonly used in the United States.
• mmol/L (millimoles per liter): Used in most other countries.

To interpret readings accurately, it's essential to know the normal ranges for each unit and use conversion tools when necessary.

8. Can I use international blood glucose meters in my country?

Yes, you can use blood glucose meters from other countries, but be mindful of the units they display. Ensure you understand whether the meter reports in mg/dL or mmol/L and convert the readings accordingly to match your healthcare provider's standards.

9. Why might my blood sugar readings vary between devices?

Variations can occur due to differences in calibration, sample size, and technology used in different devices. Environmental factors, such as temperature and humidity, can also affect readings. It's advisable to use the same device consistently and follow the manufacturer's guidelines for accurate results.

10. How can I ensure accurate blood sugar readings?

To obtain accurate blood sugar readings:

• Follow proper testing procedures: Ensure your hands are clean and dry before testing.
• Use fresh test strips: Check the expiration date and storage conditions.
• Calibrate your meter if required: Some devices need regular calibration.
• Store your meter and strips properly: Keep them in a cool, dry place.

Regularly comparing your meter's readings with laboratory results can also help ensure accuracy.

Final Thoughts

Understanding blood sugar numbers doesn’t have to be confusing. Whether you're reading mg/dL or mmol/L, now you know how to convert the numbers, what the healthy ranges are, and what you can do to keep your levels in a good place.

With the right knowledge, tools, and habits, you can feel more confident in managing your health, no matter what unit your blood sugar is measured in.

So bookmark this page, use the chart and calculator, and share it with anyone who could benefit from making blood sugar easier to understand.