By Zencalcy Editorial TeamLast reviewed About us
Blood glucose is reported in millimoles per litre in many countries and in milligrams per decilitre in others. The two scales describe the same measurement, so converting between them only requires multiplying or dividing by a fixed factor. This converter returns both numbers from a single input and shows the arithmetic.
Convert glucose between mmol/L and mg/dL.
mg/dL = mmol/L × 18.0182 mmol/L = mg/dL ÷ 18.0182
The factor 18.0182 comes from the molar mass of glucose. It is a unit conversion, not a target. Reference ranges and personal glucose goals should come from your clinician.
| Symbol | Meaning |
|---|---|
| mmol/L | Glucose concentration in millimoles per litre. |
| mg/dL | Glucose concentration in milligrams per decilitre. |
| 18.0182 | Conversion factor between the two glucose units. |
5.5 × 18.0182 = 99.1 mg/dL. Going the other way, 180 mg/dL ÷ 18.0182 = 9.99 mmol/L. Both conversions use the same fixed factor, so no rounding of the factor is needed.
The choice between mmol/L and mg/dL is historical and regional rather than scientific. Millimolar units count glucose molecules per volume, while milligrams per decilitre measure mass per volume. Because glucose has a known molar mass, the two can be linked by a single factor. Clinicians become fluent in whichever scale their laboratories use, and confusion mostly appears when people compare guidance from different countries. If you travel or use an imported meter, write the unit next to every reading. A value of 7 is normal in mmol/L but dangerously low in mg/dL, so the unit matters as much as the number. When in doubt, convert both ways and check that the result is plausible for the context.
Continue with the Estimated Average Glucose Calculator, A1c Calculator, or the HOMA-IR Calculator — or browse more diabetes tools and all health calculators.
The United States commonly uses mg/dL, while the United Kingdom, Canada, Australia and much of Europe use mmol/L. Your meter and lab report will show which unit applies locally.
These tools convert or screen laboratory values using published formulas. They do not diagnose diabetes, insulin resistance or ketoacidosis, and they do not calculate an insulin dose. Laboratory methods vary; confirm results with the reporting lab and a clinician. DKA symptoms need urgent medical care.
Reference material used to build and check this calculator:
Last reviewed: September 2026. See how we build and check every tool on the about page.
Content updated: September 2026