Cholesterol Units Converter
Estimate your cholesterol units with our free metabolic disorders calculator. See reference ranges, risk factors, and next-step guidance.
Formula
Cholesterol: mmol/L = mg/dL / 38.67; Triglycerides: mmol/L = mg/dL / 88.57
Where 38.67 is the conversion factor for cholesterol (based on molecular weight 386.65 g/mol, divided by 10 for dL to L conversion) and 88.57 is the conversion factor for triglycerides (based on average molecular weight 885.4 g/mol, divided by 10). These factors apply because mmol/L measures substance concentration (molecules) while mg/dL measures mass concentration.
Worked Examples
Example 1: US to International Lab Result Conversion
Problem: A patient in the US has: Total Cholesterol 220 mg/dL, HDL 55 mg/dL, LDL 140 mg/dL, Triglycerides 180 mg/dL. Convert all to mmol/L for a European physician.
Solution: Total Cholesterol: 220 / 38.67 = 5.69 mmol/L (Borderline High)\nHDL: 55 / 38.67 = 1.42 mmol/L (Acceptable)\nLDL: 140 / 38.67 = 3.62 mmol/L (Borderline High)\nTriglycerides: 180 / 88.57 = 2.03 mmol/L (Borderline High)\nNote: cholesterol and triglycerides use DIFFERENT conversion factors
Result: TC: 5.69 mmol/L | HDL: 1.42 mmol/L | LDL: 3.62 mmol/L | TG: 2.03 mmol/L
Example 2: International to US Lab Result Conversion
Problem: A European lab report shows Total Cholesterol 4.5 mmol/L and Triglycerides 1.2 mmol/L. Convert to mg/dL.
Solution: Total Cholesterol: 4.5 x 38.67 = 174 mg/dL (Desirable)\nTriglycerides: 1.2 x 88.57 = 106 mg/dL (Normal)\nNote: different multiplication factors are used\nIf cholesterol factor were wrongly applied to triglycerides: 1.2 x 38.67 = 46.4 mg/dL (INCORRECT)\nAlways verify which analyte you are converting
Result: TC: 174 mg/dL (Desirable) | TG: 106 mg/dL (Normal)
Frequently Asked Questions
Why do different countries use different units for cholesterol measurement?
The two main unit systems for cholesterol measurement reflect different medical traditions and scientific conventions. The United States and a few other countries use milligrams per deciliter (mg/dL), which measures the mass of cholesterol per volume of blood. Most of the world, including Europe, Australia, Canada, and much of Asia, uses millimoles per liter (mmol/L), which measures the number of cholesterol molecules per volume of blood based on the International System of Units (SI). The SI system is considered more scientifically precise because it measures substance concentration rather than mass concentration, but the mg/dL system remains deeply embedded in American medical practice, guidelines, and clinical literature. Understanding both units is essential for interpreting international medical literature and for patients traveling between countries.
How do you convert cholesterol from mg/dL to mmol/L and vice versa?
The conversion between mg/dL and mmol/L depends on the molecular weight of the specific lipid being measured. For cholesterol (total, HDL, and LDL), which has a molecular weight of 386.65 g/mol, the conversion factor is 38.67. To convert from mg/dL to mmol/L, divide by 38.67. To convert from mmol/L to mg/dL, multiply by 38.67. For example, 200 mg/dL equals 5.17 mmol/L (200 divided by 38.67). For triglycerides, which have an average molecular weight of approximately 885.4 g/mol, the conversion factor is 88.57. So triglycerides of 150 mg/dL equals 1.69 mmol/L (150 divided by 88.57). A quick approximation for cholesterol is to divide mg/dL by 39 or multiply mmol/L by 39.
Why is the conversion factor different for triglycerides compared to cholesterol?
The conversion factor differs because cholesterol and triglycerides have very different molecular weights, and the mmol/L unit is based on the number of molecules (moles) rather than mass. Cholesterol has a molecular weight of approximately 386.65 g/mol, while triglycerides are much larger molecules with an average molecular weight of approximately 885.4 g/mol. Since mmol/L counts molecules, you need more milligrams of the heavier triglyceride molecule to equal one millimole compared to the lighter cholesterol molecule. This is why the triglyceride conversion factor (88.57) is roughly 2.3 times larger than the cholesterol conversion factor (38.67). Using the wrong conversion factor is a common error that can lead to significantly inaccurate values and potentially inappropriate clinical decisions.
What are the desirable cholesterol levels in both mg/dL and mmol/L?
According to the National Cholesterol Education Program and international guidelines, desirable total cholesterol is below 200 mg/dL (5.17 mmol/L). For LDL cholesterol, optimal is below 100 mg/dL (2.59 mmol/L), with high-risk patients targeting below 70 mg/dL (1.81 mmol/L). HDL cholesterol should ideally be above 60 mg/dL (1.55 mmol/L) for cardiovascular protection, with levels below 40 mg/dL (1.03 mmol/L) considered a risk factor. Triglycerides should be below 150 mg/dL (1.69 mmol/L) for normal classification. These targets may be adjusted based on individual cardiovascular risk factors, and recent guidelines emphasize overall risk assessment over strict cholesterol cutoffs.
How should I interpret cholesterol results from an international lab report?
When reading international lab reports, first identify the unit system used (mg/dL or mmol/L), which should be clearly stated next to each result. Apply the appropriate conversion factor for each lipid type: divide cholesterol values (TC, HDL, LDL) by 38.67 to convert mg/dL to mmol/L, or divide triglycerides by 88.57. Many lab reports include reference ranges that indicate normal, borderline, and abnormal values in the unit system used. If comparing results from different laboratories or different countries, convert all values to the same unit system before comparison. Be aware that some labs report results to different decimal places, which may create apparent discrepancies that are simply rounding differences. When sharing results with healthcare providers in a different country, provide the original values with units and let them perform the conversion.
What is the relationship between cholesterol units and the International System of Units (SI)?
The International System of Units (SI) is the modern metric system adopted by most countries and scientific organizations worldwide. In the SI system, substance concentration is measured in moles per liter (mol/L) or its derivatives like millimoles per liter (mmol/L). This unit measures the number of molecules of a substance in a given volume and is considered more scientifically fundamental than mass concentration (mg/dL). The World Health Organization and most international medical organizations recommend using SI units for laboratory reporting. However, the transition has been incomplete, particularly in the United States, where mg/dL remains the standard for lipid measurements, hemoglobin, and many other lab values. The dual unit system creates confusion in international medical communication and requires constant conversion in research and clinical practice.