Blood Sugar Conversion Chart: Mg/dL, Mmol/L & A1C

A1C to Glucose Conversion Chart

An A1C conversion chart translates your Hemoglobin A1C percentage into an estimated average glucose (eAG). While A1C reflects your average blood glucose over the past 2–3 months, eAG converts that percentage into the same units (mg/dL or mmol/L) you see on your daily meter.

Note: These figures are estimates based on ADA standards. Individual biology varies.

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3 Important Readings to Consider On A Blood Sugar Conversion Chart

It’s important to understand how different blood glucose values may impact your health, since high or low blood sugar levels can have serious implications for your metabolic health and overall wellbeing.

While normal blood glucose values may vary slightly for each person, there are a few ranges you should be aware of that can help you determine if your blood sugar is optimal.

Fasting Blood Glucose Levels: 70-99 mg/dL

Blood glucose levels between 70 to 99 mg/dL, or 3.9 to 5.5 mmol/L, are considered to be normal for adults without diabetes. Some researchers have argued for a a smaller range of 70 to 90 mg/dL, to potentially lower the risk of developing prediabetes or type 2 diabetes.

Although these levels are considered optimal, fluctuation is normal and certain individuals may thrive at different blood glucose values within this range. Remember that many factors can affect your blood sugar, and there are also ways to improve your blood sugar levels over time.

However, before making significant dietary or lifestyle changes, consult with a healthcare professional or registered dietitian to discuss your individual health needs.

Fasting Blood Glucose Levels: 100-125 mg/dL 

Fasting blood glucose levels between 100 to 125 mg/dL, or 5.6 to 6.9 mmol/L, are considered elevated and are classified as outside of the normal range. This range may indicate or lead to the onset of prediabetes. A prediabetes diagnosis can put you at a greater risk of developing type 2 diabetes, high blood pressure, blood lipid disorders, and other adverse conditions.

People with elevated fasting glucose levels may want to have a conversation with a healthcare professional or a qualified dietitian or nutritionist about making lifestyle changes to stabilize their levels.

Fasting Blood Glucose Levels: 126 mg/dL or Higher 

Fasting blood glucose levels of 126 mg/dL (or 7.0 mmol/L) or higher are often associated with type 2 diabetes. This indicates the body may be experiencing significant insulin resistance or an inability to regulate glucose effectively.

It depends on your unique context. Elevated fasting glucose can result from insulin resistance, the "Dawn Phenomenon," stress, poor sleep, or genetics. Identifying the root cause often requires more than a single reading.

Why "Averages" (A1C) Don't Tell the Whole Story

Yes, your A1C matters, but it has a blind spot: variability. Two people can have the exact same A1C (e.g., 5.5%), but very different metabolic health profiles. One might have stable glucose all day, while the other experiences extreme spikes and crashes that "average out" to a normal number. This is called glycemic variability. A continuous glucose monitor (CGM) captures these daily fluctuations that a simple conversion chart or spot-check might miss.

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Understanding the Difference Between Mmol/L and Mg/dL

Both mg/dL and mmol/L are used to measure blood glucose levels in slightly different ways. However, the main distinction is simply in which area of the world each measurement is used.

The measurement of mmol/L measures the concentration of blood glucose, or the number of molecules, in one liter of blood. In contrast, the measurement mg/dL measures the concentration, or the ratio of the weight of blood glucose to liters.

Important Formulas to Keep in Mind 

Knowing the difference between these two different measurements and how to calculate them can be important as you deepen your understanding of blood sugar levels and their effect on the body.

If you don’t have access to a blood sugar conversion chart, here are two simple formulas to help you switch between these two different measurement units with ease.

Formula to Calculate Mmol/L From Mg/dL

1 mmol/L of blood glucose is equivalent to 18 mg/dL of blood glucose. So, if you're trying to calculate mmol/L from mg/dL, you can multiply the mg/dL value by 0.0555 to get the equivalent mmol/L value of blood glucose.

Here’s an Example Calculation: 

105 mg/dL x 0.0555 = 5.83 mmol/L.

If you recall the blood glucose ranges we discussed, this value would fall into the prediabetic range.

Formula to Calculate Mg/dL from Mmol/L

On the other hand, if you’re trying to convert from mmol/L to mg/dL, simply multiply the mmol/L number by 18.

Here’s a Sample Calculation:

4 mmol/L x 18 = 72 mg/dL blood glucose.

This value, as we discussed earlier, would fall within the normal adult range.
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