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Convert blood glucose levels between mg/dL and mmol/L units instantly
| Category | mg/dL | mmol/L |
|---|---|---|
| Hypoglycemia | < 70 | < 3.9 |
| Normal (Fasting) | 70 - 99 | 3.9 - 5.5 |
| Pre-diabetic (Fasting) | 100 - 125 | 5.6 - 6.9 |
| Diabetic (Fasting) | ≥ 126 | ≥ 7.0 |
| Normal (2h Post-meal) | < 140 | < 7.8 |
Blood sugar (glucose) levels can be measured in two different units: milligrams per deciliter (mg/dL) and millimoles per liter (mmol/L). The United States primarily uses mg/dL, while most other countries, including Canada, the UK, and Australia, use mmol/L. This difference exists due to international standardization efforts in laboratory medicine, where the International System of Units (SI) recommends mmol/L as the standard measurement.
Understanding both units is essential for people with diabetes who travel internationally, read medical literature from different countries, or use glucose monitoring devices manufactured in different regions. The conversion factor between these units is 18.0182, which represents the molecular weight of glucose. This means that 1 mmol/L equals 18.0182 mg/dL. Accurate conversion ensures proper diabetes management regardless of which measurement system your healthcare provider or glucose meter uses.
The conversion between mg/dL and mmol/L is straightforward using the conversion factor 18.0182. To convert from mg/dL to mmol/L, divide the mg/dL value by 18.0182. For example, if your blood sugar is 100 mg/dL, dividing by 18.0182 gives you approximately 5.55 mmol/L. Conversely, to convert from mmol/L to mg/dL, multiply the mmol/L value by 18.0182. If your reading is 7.0 mmol/L, multiplying by 18.0182 gives you approximately 126 mg/dL.
The conversion factor 18.0182 comes from the molecular weight of glucose, which is used in medical calculations to convert between mass concentration (mg/dL) and molar concentration (mmol/L). Some sources round this to 18 for simplicity, but using the precise value of 18.0182 ensures more accurate conversions, particularly important at critical diagnostic thresholds like the 126 mg/dL (7.0 mmol/L) diabetes diagnosis cutoff.
When interpreting converted values, remember that reference ranges remain consistent across both units. Normal fasting blood sugar is 70-99 mg/dL (3.9-5.5 mmol/L), pre-diabetic range is 100-125 mg/dL (5.6-6.9 mmol/L), and diabetic range is 126 mg/dL or higher (7.0 mmol/L or higher). Always verify your glucose meter's unit setting to avoid dangerous misinterpretation of readings.
This calculator is for educational purposes only and should not replace professional medical advice. Always consult with your healthcare provider for diabetes management decisions. Blood sugar targets may vary based on individual health conditions, age, and treatment plans.
The difference stems from international standardization efforts. The International System of Units (SI) recommends mmol/L as it's based on molecular concentration rather than mass. Most countries adopted SI units, but the United States continues to use mg/dL in clinical practice.
Misreading units can be extremely dangerous. A reading of 5 mg/dL indicates severe hypoglycemia requiring immediate treatment, while 5 mmol/L (90 mg/dL) is normal. Always verify your meter's unit setting before interpreting results.
Some meters allow unit switching, but many have the unit permanently set based on the region where they were sold. Check your meter's manual or contact the manufacturer to determine if your model supports unit changes.
This number represents the molecular weight of glucose. It's the precise factor needed to convert between mass concentration (mg/dL) and molar concentration (mmol/L). Some sources round to 18, but 18.0182 provides more accurate conversions.
Yes, the target ranges are equivalent when properly converted. Normal fasting is 70-99 mg/dL or 3.9-5.5 mmol/L. Pre-diabetic is 100-125 mg/dL or 5.6-6.9 mmol/L. Diabetic is ≥126 mg/dL or ≥7.0 mmol/L.
Most healthcare providers are familiar with both units and can easily convert if needed. However, if you're sharing data across different healthcare systems or countries, providing readings in both units can prevent confusion and ensure accurate interpretation.
Yes, CGMs also display readings in either mg/dL or mmol/L depending on the region and device settings. Most CGM apps allow you to view data in either unit, making it easier to communicate with healthcare providers who use different measurement systems.
It's helpful to memorize key values like 100 mg/dL ≈ 5.5 mmol/L (normal/pre-diabetic threshold) and 126 mg/dL = 7.0 mmol/L (diabetic threshold). However, for precise conversions, always use a calculator or conversion chart to ensure accuracy.
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