Quickly convert blood glucose between mmol/L (UK and most of the world) and mg/dL (US, Germany, France). Type any value, get the other instantly. Uses the standard conversion factor 18.018 mg/dL per 1 mmol/L.
Blood glucose unit converter
The conversion formula
mg/dL = mmol/L × 18.018
mmol/L = mg/dL ÷ 18.018
The factor 18.018 comes from glucose’s molecular weight (180.16 g/mol) and the conversion between dL and L. For most clinical purposes, “× 18” or “÷ 18” is close enough: the calculator above uses the precise value.
Quick reference table
| mmol/L | mg/dL | Typical context |
|---|---|---|
| 3.0 | 54 | Hypoglycaemia: treat immediately |
| 3.9 | 70 | ADA hypoglycaemia threshold |
| 4.0 | 72 | Lower bound of typical fasting target |
| 5.6 | 100 | Upper bound of normal fasting glucose |
| 7.0 | 126 | Diabetes diagnosis threshold (fasting) |
| 7.8 | 140 | 2-hour post-meal threshold for impaired glucose tolerance |
| 10.0 | 180 | Common upper limit for time-in-range (TIR) |
| 11.1 | 200 | Diabetes diagnosis threshold (random / OGTT 2h) |
| 13.9 | 250 | Significant hyperglycaemia |
| 16.7 | 300 | Mark: check ketones in type 1 diabetes |
FAQ
Why do different countries use different units?
mmol/L is the SI unit and is used in the UK, Europe, Australia, Canada, and most of Asia. mg/dL is the older “ conventional” unit and remains standard in the US, France, Germany, and parts of Latin America. Both measure the same thing: the concentration of glucose in the blood, just on different scales.
Does my CGM use mmol/L or mg/dL?
Whichever your country’s regulator allows. UK Dexcom, Libre, and Eversense devices default to mmol/L; US devices default to mg/dL. Most allow you to switch in the app settings.
Quick mental conversion?
Multiply mmol/L by 18 to get a close mg/dL. So 5 → 90, 7 → 126, 10 → 180. To go the other way: divide by 18. So 100 → 5.5, 200 → 11.1.
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Reviewed: May 2026.