Blood Sugar Converter
Convert blood glucose between mg/dL and mmol/L instantly.
Includes a reference table of normal, prediabetic, and diabetic glucose ranges in both units.
Type in either field — the other updates instantly.
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Blood glucose is measured in two different units depending on the country.
mg/dL (milligrams per deciliter) is used in the United States, Japan, France, Egypt, and Colombia. mmol/L (millimoles per liter) is used in the UK, Canada, Australia, China, and most of Europe.
Conversion formula:
- mmol/L = mg/dL ÷ 18.0156
- mg/dL = mmol/L × 18.0156
The factor 18.0156 comes from the molecular weight of glucose (180.156 g/mol) divided by 10.
Common reference ranges (fasting):
| Status | mg/dL | mmol/L |
|---|---|---|
| Normal | 70–99 | 3.9–5.5 |
| Pre-diabetic | 100–125 | 5.6–6.9 |
| Diabetic | 126+ | 7.0+ |
The two units exist because they measure glucose differently. mg/dL counts the mass of glucose in a volume of blood, while mmol/L counts the number of glucose molecules. Both are valid, they just answer slightly different questions, which is why the conversion runs through glucose’s molecular weight.
In practice the gap matters most when you’re reading advice or a meter set to the other country’s unit. A fasting reading of 90 mg/dL is 5.0 mmol/L, and the diabetes threshold of 126 mg/dL is 7.0 mmol/L. The numbers look wildly different, so it’s easy to misread a perfectly normal value as alarming, or the reverse. This is general information for converting between units, not medical advice; for anything about your own health, talk to a doctor.
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