Blood Glucose Converter
Convert blood glucose measurements between mg/dL (used in the US, Germany, Japan) and mmol/L (used in the UK, Canada, Australia, and most of the world).
Formula
To convert blood glucose from mg/dL to mmol/L:
mmol/L = mg/dL ÷ 18.0182
To convert blood glucose from mmol/L to mg/dL:
mg/dL = mmol/L × 18.0182
To convert mg/dL to mmol/L for glucose. This factor is specific to glucose. Other substances (cholesterol, creatinine, etc.) use different factors.
Where 18.0182 comes from
Glucose has a molar mass of 180.156 g/mol. Converting mg/dL to mmol/L requires dividing by 18.0156 (the molar mass in g/mol / 10 for the dL-to-L factor). In practice, the widely used value is 18.0182, which is derived from the more precise molar mass of glucose (180.182 g/mol) as it is defined in clinical chemistry.
Note: some sources use 18.0 or 18.016 as a rounded value. The difference is negligible for clinical interpretation but can matter for research applications.
Worked Examples
Example 1: 100 mg/dL to mmol/L
- Start: 100 mg/dL.
- Divide: 100 ÷ 18.0182 = 5.54996.
- Result: 100 mg/dL ≈ 5.55 mmol/L. This is a normal fasting blood glucose value.
Example 2: 126 mg/dL to mmol/L
- Start: 126 mg/dL.
- Divide: 126 ÷ 18.0182 = 6.99293.
- Result: 126 mg/dL ≈ 6.99 mmol/L. This is the diagnostic threshold for diabetes in the US (fasting).
Example 3: 7.0 mmol/L to mg/dL
- Start: 7.0 mmol/L.
- Multiply: 7.0 × 18.0182 = 126.1274.
- Result: 7.0 mmol/L ≈ 126 mg/dL. This is the diagnostic threshold for diabetes internationally.
Example 4: 5.5 mmol/L to mg/dL
- Start: 5.5 mmol/L.
- Multiply: 5.5 × 18.0182 = 99.1001.
- Result: 5.5 mmol/L ≈ 99 mg/dL. A normal fasting value.
Conversion Table
| mg/dL | mmol/L | Context |
|---|---|---|
| 54 | 3.0 | Hypoglycemia threshold |
| 70 | 3.9 | Low-normal fasting |
| 80 | 4.4 | Normal fasting |
| 90 | 5.0 | Normal fasting |
| 100 | 5.5 | Upper end of normal fasting |
| 110 | 6.1 | Impaired fasting glucose (WHO) |
| 126 | 7.0 | Diabetes diagnostic threshold (fasting) |
| 140 | 7.8 | Upper normal after meal |
| 180 | 10.0 | Elevated post-meal |
| 200 | 11.1 | Diabetes diagnostic threshold (random or OGTT) |
| 250 | 13.9 | High |
| 400 | 22.2 | Very high |
Where Each Unit Is Used
- mg/dL — United States, Germany, Japan, France, and some other countries.
- mmol/L — United Kingdom, Canada, Australia, New Zealand, China, and most of the world.
Both units describe the same physical quantity; the choice is a matter of national convention. Medical professionals are trained in both and can convert easily when reading international literature.
Safety Notes
- This tool converts units only. It does not interpret values, diagnose diabetes, or recommend treatment.
- Reference ranges differ between laboratories and clinical guidelines. Always use the range specified by the laboratory that produced the result.
- Blood glucose meters may display in either unit; check your meter's setting or consult the user manual.
- If you have concerns about your blood glucose, consult a qualified healthcare professional.
Related Converters
Frequently Asked Questions
How do you convert mg/dL to mmol/L for glucose?
Divide the mg/dL value by 18.0182. For example, 100 mg/dL ÷ 18.0182 ≈ 5.55 mmol/L.
How do you convert mmol/L to mg/dL?
Multiply the mmol/L value by 18.0182. For example, 5.5 mmol/L × 18.0182 ≈ 99 mg/dL.
Is the conversion factor the same for all substances?
No. Each substance has its own conversion factor based on its molar mass. Cholesterol uses 38.67, creatinine uses 88.4, and glucose uses 18.0182. Using the wrong factor produces wrong results.
What is a normal blood glucose level?
Reference ranges vary by laboratory and clinical context. As a general guide, normal fasting glucose is roughly 70–100 mg/dL (3.9–5.5 mmol/L). Consult your healthcare provider for personalized interpretation.
Is this medical advice?
No. This is a unit conversion tool. It does not diagnose, treat, or evaluate any medical condition. Always consult a qualified healthcare professional.