Convert a blood sugar reading between mg/dL and mmol/L using the standard 18.0182 clinical conversion factor, and see where it falls against ADA reference ranges.
Quick Facts
Conversion factor
1 mmol/L = 18.0182 mg/dL
Derived from glucose's molar mass (about 180.16 g/mol)
Units by region
US: mg/dL | Most other countries: mmol/L
Same blood sugar amount, two different unit systems
Results
Calculated
Converted value
—
In the opposite unit
In mg/dL
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US standard unit
In mmol/L
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International (SI) unit
ADA reference range
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Screening interpretation only
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How to use this calculator
Enter a blood sugar reading, choose the unit it was measured in (mg/dL or mmol/L), and optionally pick the reading type so the interpretation uses the right ADA reference range. Click Calculate to see the value converted to the other unit, both units side by side, and a plain-language range interpretation. Click Clear to reset all fields.
The conversion formula
Blood glucose is reported in two units worldwide. The United States uses mg/dL (milligrams of glucose per deciliter of blood), a mass concentration. Most other countries and the scientific SI system use mmol/L (millimoles per liter), a molar concentration. The two are related by glucose's molar mass:
The factor 18.0182 comes from dividing glucose's molar mass, about 180.16 grams per mole, by 10 (to convert deciliters to liters and grams to milligrams consistently). For example, 126 mg/dL divided by 18.0182 is about 7.0 mmol/L — the ADA's fasting diabetes threshold in both units.
Interpreting the results
The highlighted card shows your value converted into the opposite unit. The two supporting cards show the exact reading in both mg/dL and mmol/L so you can compare against any chart or lab report. The last card places the mg/dL value against standard ADA screening ranges for the reading type you selected (fasting, 2-hour post-meal, or random) — this is a screening reference only, not a diagnosis.
Frequently Asked Questions
How do you convert mg/dL to mmol/L?
Divide the mg/dL value by 18.0182 to get mmol/L. For example, 100 mg/dL divided by 18.0182 is about 5.6 mmol/L. To go the other way, multiply mmol/L by 18.0182 to get mg/dL. The factor comes from glucose's molar mass of about 180.16 g/mol.
What is a normal blood sugar level?
Under ADA guidance, a normal fasting blood sugar is under 100 mg/dL (5.6 mmol/L). 100-125 mg/dL (5.6-6.9 mmol/L) fasting is considered prediabetes, and 126 mg/dL (7.0 mmol/L) or higher fasting indicates the diabetes range. Two hours after eating, under 140 mg/dL (7.8 mmol/L) is normal. These are screening reference ranges, not a diagnosis.
Why do the US and other countries use different units?
The United States reports blood sugar as a mass concentration, mg/dL. Most other countries, along with the SI system used in scientific literature, report it as a molar concentration, mmol/L. Both describe the same underlying quantity of glucose in the blood, just in different units.
Is this calculator a substitute for a lab test or my doctor?
No. This tool only converts and re-labels a number you already have; it does not measure blood sugar. Diagnosis of prediabetes or diabetes requires laboratory testing (such as a fasting plasma glucose, oral glucose tolerance test, or A1c) interpreted by a healthcare provider. Always discuss results with your doctor.