Blood Sugar Converter
Convert blood glucose between mg/dL and mmol/L.
Results update as you type.
This calculator provides estimates based on population research. Results are not medical advice. Consult a qualified healthcare provider before making health or nutrition decisions.
How it works
A blood sugar converter restates a blood glucose reading in the other of the two units used worldwide: milligrams per decilitre (mg/dL) and millimoles per litre (mmol/L). It works by dividing or multiplying by 18.0182, the conversion factor specific to glucose, so a value entered in one unit appears correctly in the other. This lets a reading from one meter, guideline or country be understood in the unit someone is used to. This matters because the two units are split geographically. The United States, Germany and a few other countries report glucose in mg/dL; the United Kingdom, Canada, Australia and much of the rest of the world use mmol/L. A traveller, a person reading an international guideline, or a clinician comparing meters can face a number in an unfamiliar unit, and glucose targets are narrow enough that translating them correctly matters. The factor 18.0182 comes from the molar mass of glucose, about 180.16 grams per mole: because a mole per litre relates mass to amount of substance, converting a mass concentration (mg/dL) to a molar concentration (mmol/L) uses that molar mass, and the decilitre-to-litre step folds into the same constant. This tool is a unit converter for glucose only and does not interpret readings or give medical advice. People with diabetes, carers, travellers and health professionals all use a blood sugar converter to read glucose figures on whichever scale they know.
Convert between mg/dL and mmol/L using the glucose factor 18.0182
To convert milligrams per decilitre to millimoles per litre, divide by 18.0182; to go the other way, multiply by 18.0182. The constant is fixed by the molar mass of glucose, about 180.16 grams per mole, combined with the decilitre-to-litre relationship, so it applies specifically to glucose and not to other blood substances. Because the factor is constant, the conversion is a single exact multiply or divide in either direction.
Source:International System of Units (SI) — NIST
We review all our tools from time to time to ensure accuracy.
Worked example
How to use this calculator
- 1
Enter your values
Enter value, from and to.
- 2
Adjust the options
Fine-tune any options to match your situation.
- 3
Read your result
Converted glucose updates instantly as you type — no button to press.
Frequently asked questions
How do I convert mg/dL to mmol/L for blood sugar?
Divide the mg/dL figure by 18.0182 to get mmol/L. So a fasting reading of 100 mg/dL is about 5.55 mmol/L, and 180 mg/dL is about 9.99 mmol/L. To go the other way, multiply mmol/L by 18.0182. The factor is specific to glucose because it derives from glucose's molar mass, so it should not be used for other blood measurements.
Why is the conversion factor 18.0182?
It comes from the molar mass of glucose, about 180.16 grams per mole. Converting a mass-based concentration in milligrams per decilitre to a molar concentration in millimoles per litre requires dividing by the molar mass, and the decilitre-to-litre unit step is folded into the same constant, yielding 18.0182. Because it is tied to glucose specifically, the same factor does not apply to cholesterol or other blood analytes.
Which countries use mg/dL versus mmol/L?
The United States, Germany, France, Japan and several others report blood glucose in mg/dL, while the United Kingdom, Canada, Australia, China and much of the rest of the world use mmol/L. This split is why travellers and people reading international guidelines often need to convert. The number looks very different — 5.5 mmol/L versus about 100 mg/dL — even though it is the same glucose level.
What is a normal blood sugar level?
General reference figures often cite a fasting level around 70 to 100 mg/dL, roughly 3.9 to 5.6 mmol/L, but exact targets depend on the individual, the time relative to meals and clinical guidance. This converter only changes units and does not interpret whether a reading is normal or a target is met. Always rely on a healthcare professional and the relevant guidelines for interpretation.
Does this converter give medical advice?
No. It converts a glucose figure between mg/dL and mmol/L and nothing more. It does not diagnose, interpret a reading, or recommend any action, and it must not replace a glucose meter, laboratory test or professional judgement. If you have questions about your blood sugar, targets or treatment, consult a doctor, diabetes educator or pharmacist rather than relying on a unit conversion.