Type a value in either field and the other updates instantly. mg/dL and mmol/L describe the same glucose level in different units: 1 mmol/L equals about 18 mg/dL.
How the conversion works
mg/dL (milligrams per decilitre) measures the weight of glucose in a volume of blood, while mmol/L (millimoles per litre) counts glucose molecules. Because glucose has a molar mass of about 180.16 g/mol, one mmol/L equals 18.016 mg/dL. In practice everyone rounds to 18:
- mmol/L to mg/dL: multiply by 18 (5.5 mmol/L is about 99 mg/dL)
- mg/dL to mmol/L: divide by 18 (100 mg/dL is about 5.6 mmol/L)
Blood sugar conversion chart
Common values side by side. The 70 to 180 mg/dL band (3.9 to 10.0 mmol/L) is the standard CGM target range used for time in range.
| mmol/L | mg/dL | Typically described as |
|---|---|---|
| 2.2 | 40 | Very low (below 54 mg/dL) |
| 2.8 | 50 | |
| 3.3 | 60 | Low (54 to 69 mg/dL) |
| 3.9 | 70 | Standard CGM target range (70 to 180 mg/dL) |
| 5.0 | 90 | |
| 5.5 | 99 | |
| 6.7 | 120 | |
| 8.3 | 150 | |
| 10.0 | 180 | |
| 11.1 | 200 | High (above 180 mg/dL) |
| 13.9 | 250 | |
| 16.7 | 300 | Very high (above 250 mg/dL) |
| 22.2 | 400 |
Prefer paper? Download the printable chart (PDF) and stick it on the fridge or in a school bag.
These bands follow the international consensus targets for CGM users. New to sensors? Start with our plain-English CGM guide, or check how much of your day sits inside the band with the Time in Range calculator.
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Frequently asked questions
How do I convert mmol/L to mg/dL?
Multiply the mmol/L value by 18. For example, 5.5 mmol/L is about 99 mg/dL. The precise factor is 18.016, because glucose has a molar mass of about 180.16 g/mol, but 18 is accurate enough for everyday use.
How do I convert mg/dL to mmol/L?
Divide the mg/dL value by 18 (or multiply by 0.0555). For example, 100 mg/dL is about 5.6 mmol/L.
Which countries use mg/dL and which use mmol/L?
The United States and a number of other countries report blood glucose in mg/dL, while the United Kingdom, Canada, Australia and most of Europe use mmol/L. Both describe exactly the same glucose level, only the unit differs, which is why meters, CGM apps and lab reports can look so different between countries.
What is a normal blood sugar level in both units?
For people without diabetes, fasting glucose is typically about 70 to 99 mg/dL (3.9 to 5.5 mmol/L). For people with diabetes who use a CGM, the international consensus uses 70 to 180 mg/dL (3.9 to 10.0 mmol/L) as the standard target range for time in range. Targets are individual, so always follow the range agreed with your care team.
Can Sugar Sense show both units?
Yes. Sugar Sense lets you switch between mg/dL and mmol/L at any time, and the change applies everywhere at once: the app, the Apple Watch, widgets and the Live Activity.
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This tool is for education only. It is not medical advice, it does not replace laboratory testing, and it must never be used for insulin dosing or other treatment decisions. Always work with your healthcare team. See our full medical disclaimer.
