Blood Glucose Conversion from mg/dL to mmol/L
To convert blood glucose from mg/dL to mmol/L, divide the mg/dL value by 18. 1
Conversion Formula
- To convert from mg/dL to mmol/L: divide the mg/dL value by 18 1
- Example: 126 mg/dL ÷ 18 = 7.0 mmol/L 1
- Example: 180 mg/dL ÷ 18 = 10.0 mmol/L 1
Common Blood Glucose Reference Values in Both Units
Normal and Diagnostic Values
- Normal fasting glucose: 70-110 mg/dL (3.9-6.1 mmol/L) 2
- Impaired fasting glucose (IFG): 100-125 mg/dL (5.6-6.9 mmol/L) 1
- Diabetes diagnosis threshold (fasting): ≥126 mg/dL (≥7.0 mmol/L) 1
- Diabetes diagnosis threshold (2-hour OGTT): ≥200 mg/dL (≥11.1 mmol/L) 1
Critical Values
- Hypoglycemia alert: <70 mg/dL (<3.9 mmol/L) 1
- Severe hypoglycemia: <40 mg/dL (<2.2 mmol/L) 1
- Hyperglycemia requiring attention: >250 mg/dL (>13.9 mmol/L) 1
- Severe hyperglycemia: >300 mg/dL (>16.7 mmol/L) 1
Quick Reference Conversion Table
| mg/dL | mmol/L |
|---|---|
| 70 | 3.9 |
| 100 | 5.6 |
| 126 | 7.0 |
| 140 | 7.8 |
| 180 | 10.0 |
| 200 | 11.1 |
| 250 | 13.9 |
| 300 | 16.7 |
Important Considerations
- When reviewing research or international guidelines, pay attention to which unit is being used, as different countries prefer different units 1
- North America typically uses mg/dL, while most other countries use mmol/L 1
- For accurate interpretation of glucose values in research, always check which unit is being reported 1
- When using continuous glucose monitoring (CGM) systems, be aware that some devices may allow switching between units 3
Common Pitfalls to Avoid
- Confusing the conversion factors (multiplying by 18 instead of dividing) 1
- Misinterpreting threshold values when reading international literature 1
- Failing to note which unit is being used when interpreting test results 1
- Not recognizing that different sample types (plasma vs. whole blood) may have different reference ranges even in the same units 1