mmol/L to mg/dL Converter
5.5 mmol/L glucose is 99.1 mg/dL, and 100 mg/dL is 5.5499 mmol/L. This glucose converter switches between mmol/L and mg/dL using the fixed glucose factor of 18.0182. It is built for blood glucose only. Enter a value, choose the direction you need, and the tool multiplies or divides by that factor to return the converted number along with the units on both sides of the conversion. Blood glucose is reported in mmol/L in most countries that use SI units, while the United States and a few other countries still report it in mg/dL. That difference shows up on lab reports, glucose meters, continuous glucose monitors, and international medical literature, so a reliable unit converter matters whenever you are comparing numbers from different sources. This tool exists specifically for that unit change, not for interpreting whether a number is high, low, or typical.
Quick answer
For glucose, 1 mmol/L equals 18.0182 mg/dL.
Glucose uses the factor 18.0182. Cholesterol does not. Total, LDL, and HDL cholesterol use a different factor, about 38.67.
This tool converts units only. It does not tell you whether a glucose result is normal or how to treat it.
What this tells you
- •For glucose, 1 mmol/L equals 18.0182 mg/dL.
- •To convert mmol/L to mg/dL, multiply the glucose value by 18.0182.
- •To convert mg/dL to mmol/L, divide the glucose value by 18.0182.
- •Cholesterol uses a different factor, about 38.67, so this calculator is glucose only and should never be used for cholesterol values.
- •The glucose factor of 18.0182 comes from the molecular weight of glucose and is a fixed scientific constant, not a rounded estimate.
How to Use
- 1Enter the glucose value you want to convert, such as a lab result or a glucose meter reading.
- 2Choose the direction, either mmol/L to mg/dL or mg/dL to mmol/L, depending on which unit you are starting from.
- 3Click Convert to see the converted glucose value along with the input and output units.
- 4Double-check the direction before reading the result, since entering the same number with the wrong direction produces a very different, incorrect value.
- 5If you are converting cholesterol instead of glucose, stop and use a cholesterol-specific converter, since this tool's factor does not apply to cholesterol.
How It Works
Formula
Glucose mg/dL = glucose mmol/L × 18.0182
Glucose mmol/L = glucose mg/dL ÷ 18.0182Blood glucose uses a fixed molecular-weight conversion. Multiply by 18.0182 to move from mmol/L to mg/dL, or divide by 18.0182 to go the other way. This factor comes from glucose's molar mass and the standard relationship between molar concentration and mass concentration, so it does not change based on lab, country, or measurement method. This factor is for glucose only. Cholesterol values use a different molecular weight and therefore a different factor, so they cannot share this formula.
Calculation note: values are processed in the order shown above, using the current input units.
Worked Examples
Convert 5.5 mmol/L glucose to mg/dL
Multiply 5.5 by 18.0182 to get 99.1001 mg/dL, which rounds to 99.1 mg/dL. This is a common fasting-range value expressed in the two most widely used glucose units.
Convert 100 mg/dL glucose to mmol/L
Divide 100 by 18.0182 to get 5.54994394557 mmol/L, which rounds to 5.5499 mmol/L. This shows how a round mg/dL number does not always convert to a round mmol/L number.
Convert 7 mmol/L glucose to mg/dL
Multiply 7 by 18.0182 to get 126.1274 mg/dL, which rounds to 126.13 mg/dL. This value is often referenced when comparing glucose readings across different unit standards.
Convert 180 mg/dL glucose to mmol/L
Divide 180 by 18.0182 to get 9.98989... mmol/L, which rounds to 9.9899 mmol/L. Rounding matters more at this scale since the fourth decimal place can shift the displayed value.
Common Glucose Unit Conversions
Quick glucose lookups using the glucose factor of 18.0182.
| mmol/L | mg/dL |
|---|---|
| 4.0 | 72.1 |
| 5.0 | 90.1 |
| 5.5 | 99.1 |
| 7.0 | 126.1 |
| 10.0 | 180.2 |
This table is for glucose only. Total, LDL, and HDL cholesterol use a different factor, about 38.67.
Why glucose and cholesterol use different factors
Unit conversion factors between mmol/L and mg/dL are not universal. Each factor depends on the molecular weight of the specific substance being measured, so glucose, cholesterol, and other lab values each have their own conversion number.
Glucose has a molecular weight that produces the 18.0182 factor used in this tool. Cholesterol has a different molecular weight, which produces a different factor of about 38.67. Using the wrong factor for the wrong substance produces a converted number that looks plausible but is actually incorrect, which is why this tool is scoped to glucose only.
Common mistakes
- Using the glucose factor for cholesterol results. Cholesterol needs a different factor, so applying this converter to a cholesterol number produces an incorrect value.
- Rounding too early, especially when converting mg/dL to mmol/L, since the fourth decimal place can matter for that direction.
- Treating a converted value as a diagnosis instead of a unit change. This tool only changes the unit, it does not interpret the number.
- Selecting the wrong conversion direction, which produces a result that looks numeric and plausible but represents the wrong calculation entirely.
- Comparing a fasting glucose reading in one unit against a post-meal reading in another unit without confirming both values were measured under the same conditions.
Limitations
This tool converts glucose units only. It does not tell you whether a result is normal, fasting, post-meal, capillary, venous, or appropriate for your personal treatment plan. Cholesterol values use a different factor, about 38.67, and should not be converted with this calculator. The tool also does not account for lab-specific calibration differences, which can cause small variations between two devices reporting the same blood sample.
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