Blood Glucose Unit Converter

Calculator

How we calculate it

mg/dL and mmol/L describe the same amount of glucose in blood using two different kinds of unit. mg/dL is a mass concentration — milligrams of glucose per deciliter of blood. mmol/L is a molar concentration — millimoles of glucose molecules per liter. Converting between them requires the molar mass of glucose, 180.156 grams per mole, which gives a conversion factor of 18.0182: one mmol/L equals 18.0182 mg/dL. This calculator applies that factor directly, with no rounding until the final display, and validates the entered value in the unit you actually typed rather than after conversion, so an out-of-range warning always refers to a number you recognize. Note that some printed conversion tables round intermediate values, which is why a table may show 100 mg/dL as 5.6 mmol/L where the exact conversion is 5.5499, shown here as 5.5.

Important limitations

• Converting a unit does not change what a value means clinically. How a glucose reading is interpreted depends on when it was taken — fasting, before a meal, after a meal, or at random.
• Home meters and laboratory analysers are not perfectly interchangeable. Regulatory standards permit home meters a margin of error against a laboratory plasma glucose measurement.
• Capillary fingerstick whole blood and venous plasma are not identical samples, although most modern meters report a plasma-equivalent value.
• Continuous glucose monitors measure interstitial fluid rather than blood, and lag behind blood glucose when levels are changing quickly.
• The fasting ranges shown apply to a fasting sample in non-pregnant adults, and are screening ranges rather than a diagnosis.