Blood Glucose Conversion Calculator
Blood glucose (blood sugar) is measured in different units depending on the country. The United States uses milligrams per decilitre (mg/dL), while most of the world uses millimoles per litre (mmol/L). This difference can cause confusion for people with diabetes who travel internationally, use international health resources, or read research literature. This calculator converts instantly between both units in either direction. It also displays reference ranges for fasting glucose, pre-meal glucose, postprandial glucose, and hypoglycaemia levels so you can contextualise any reading against clinical guidelines from the American Diabetes Association.
Conversion formula
mmol/L = mg/dL / 18.018
mg/dL = mmol/L x 18.018
Conversion factor = 18.018 (glucose molecular weight / 10)
ADA fasting ranges: Normal <100 mg/dL (5.6 mmol/L); Prediabetes 100-125 mg/dL (5.6-6.9); Diabetes ≥126 mg/dL (7.0).
Blood glucose: frequently asked questions
What is the conversion factor between mg/dL and mmol/L?
The conversion factor is 18.018. To convert from mg/dL to mmol/L, divide by 18.018 (or multiply by 0.0555). To convert from mmol/L to mg/dL, multiply by 18.018. This factor derives from glucose's molecular weight of 180.18 g/mol.
Which units are used in which countries?
The United States, Japan, and several other countries use mg/dL. Most of Europe, Canada, Australia, New Zealand, and international guidelines use mmol/L. If you travel internationally with diabetes, knowing both units and the conversion factor is essential for safe glucose management.
What is a normal fasting blood glucose?
Normal fasting blood glucose is below 100 mg/dL (5.6 mmol/L). Prediabetes (impaired fasting glucose) is 100-125 mg/dL (5.6-6.9 mmol/L). Diabetes is diagnosed at 126 mg/dL (7.0 mmol/L) or above on two occasions. These are ADA criteria.
What is hypoglycaemia?
Hypoglycaemia is abnormally low blood glucose, generally defined as below 70 mg/dL (3.9 mmol/L) for people with diabetes. Clinically significant hypoglycaemia (Level 2) is below 54 mg/dL (3.0 mmol/L). Symptoms include shakiness, sweating, confusion, and in severe cases, loss of consciousness.
What is the target post-meal blood glucose?
The ADA recommends a 2-hour postprandial glucose below 180 mg/dL (10.0 mmol/L) for people with diabetes. For non-diabetic individuals, 2-hour postprandial glucose rarely exceeds 140 mg/dL (7.8 mmol/L). Levels above 140-199 mg/dL (7.8-11.0) 2 hours after a glucose load indicate impaired glucose tolerance.
Official sources
- American Diabetes Association: Diagnosis of Diabetes.
- National Institute of Diabetes and Digestive and Kidney Diseases: Blood Glucose Test.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.