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Blood Sugar Converter

Blood glucose is reported in mg/dL in the United States and in mmol/L across most of Europe and the Commonwealth. One mmol/L equals 18.0182 mg/dL, so divide a mg/dL reading by 18 to get mmol/L, or multiply the other way.

Decimals
Millimoles per litre
5.55mmol/L

Reference ranges vary by country, by lab, and by whether the reading was taken fasting. Use the range your own clinician gave you.

Common values
Milligrams per decilitreMillimoles per litre
70 mg/dL3.885 mmol/L
90 mg/dL4.9949 mmol/L
100 mg/dL5.5499 mmol/L
126 mg/dL6.9929 mmol/L
140 mg/dL7.7699 mmol/L
180 mg/dL9.9899 mmol/L
200 mg/dL11.0999 mmol/L
250 mg/dL13.8749 mmol/L
300 mg/dL16.6498 mmol/L

How to convert blood sugar between mg/dL and mmol/L

  1. Type your reading

    Enter the number from your meter or lab report into either field, whichever unit it came in.

  2. Read the other unit

    The opposite field updates as you type, so there is no button to press.

  3. Set the precision

    Pick how many decimal places to show. Two is enough for mmol/L and zero suits mg/dL.

  4. Copy or compare

    Copy the converted value, or check it against the table of common readings below.

Why use this tool

Both directions in one field pair

Edit either side and the other follows. There is no separate mode to switch between mg/dL and mmol/L.

The glucose-specific factor

Conversion uses 18.0182, which comes from the molar mass of glucose, rather than a rounded 18 that drifts at higher readings.

A table of common readings

Fasting, pre-meal, and post-meal values are listed in both units so you can place a number without doing the arithmetic.

Glucose only, on purpose

Cholesterol and other blood analytes use different molar masses, so they are deliberately left out rather than converted incorrectly.

Runs entirely in your browser

Readings you type are never sent anywhere and are not stored.

About this tool

Blood glucose is measured in two different units depending on where you are. The United States, Germany, France, Japan and a few others report milligrams per decilitre, while the United Kingdom, Australia, Canada, China and most of Europe report millimoles per litre. The numbers look nothing alike: a normal fasting reading is about 90 in mg/dL and about 5 in mmol/L, which makes reading advice written for the other system genuinely confusing.

The two are related by the molar mass of glucose, 180.156 grams per mole, which works out to 18.0182 mg/dL for every 1 mmol/L. This tool uses that full factor rather than the rounded 18 you often see, because the rounding error grows with the reading and matters most at the high values where accuracy counts. Type into either field and the other updates live, so you can go in whichever direction you need.

This is a unit conversion, not medical advice, and it cannot tell you whether a reading is good or bad. Target ranges differ by country, by laboratory, by time of day and by individual, so the range your own clinician gave you is the one that applies. If you are converting other lab values, note that each analyte needs its own molar mass and cannot use this factor. For general unit work there is the unit converter, and for percentage change between two readings there is the percentage calculator.

Frequently asked questions

How do I convert mg/dL to mmol/L?
Divide the mg/dL value by 18.0182. A reading of 100 mg/dL is 5.55 mmol/L, and 126 mg/dL is 6.99 mmol/L. To go the other way, multiply the mmol/L value by 18.0182.
Why 18.0182 and not just 18?
The factor comes from the molar mass of glucose, 180.156 grams per mole. Rounding it to 18 introduces a small error that grows with the reading: at 300 mg/dL the rounded factor is off by about 0.06 mmol/L. This tool uses the full value.
Which countries use which unit?
mg/dL is standard in the United States, Germany, France, Japan, Israel and India. mmol/L is standard in the United Kingdom, Ireland, Australia, New Zealand, Canada, China and most of Europe. Some lab reports print both.
Can I use this for cholesterol or other blood tests?
No. The factor here is specific to glucose because it is derived from the molar mass of the glucose molecule. Cholesterol, triglycerides and other analytes each have their own molar mass and need their own factor.
Does it tell me if my reading is normal?
No. It converts units and nothing else. Target ranges vary by country, by lab, by whether the sample was fasting, and by the person, so the range your clinician gave you is the one to use.
Is my data sent anywhere?
No. The conversion runs entirely in your browser. Nothing you type is uploaded, logged, or stored.

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