Cholesterol & Triglyceride Converter (mg/dL ⇄ mmol/L)

Understanding the cholesterol unit converter — concept and principle

Blood lipid results are reported in mg/dL in the United States, Korea and Japan, and in mmol/L in Europe, Canada, Australia and many other countries. This converter switches total, LDL and HDL cholesterol or triglyceride values between the two units, so you can compare a lab report from abroad with guidelines or earlier results written in the other unit.

mg/dL weighs the cholesterol; mmol/L counts its molecules.

How it is calculated

Cholesterol: mmol/L = mg/dL ÷ 38.67, and mg/dL = mmol/L × 38.67.
Triglycerides: mmol/L = mg/dL ÷ 88.57, and mg/dL = mmol/L × 88.57.

The calculator shows mmol/L to two decimals and mg/dL as a whole number. The factor depends on the substance, so choose the right test before converting.

The principle

mg/dL is a mass concentration; mmol/L counts molecules. To go from one to the other you need the molar mass. Cholesterol (C₂₇H₄₆O) has a molar mass of about 386.65 g/mol, so 1 mmol/L = 386.65 mg/L = 38.67 mg/dL (a deciliter is one tenth of a liter). HDL and LDL values are reported as the cholesterol they carry, so they use the same factor. Triglycerides are a mixture of molecules; laboratories use a factor close to the molar mass of triolein, about 885 g/mol, which gives 88.57.

Worked example

Default: cholesterol, 200 mg/dL to mmol/L.

Factor for cholesterol: 38.67.
200 ÷ 38.67 = 5.1720…
Rounded to two decimals: 5.17 mmol/L.

How to read the result

Widely cited adult cut-offs from the US National Cholesterol Education Program (ATP III) are:

Total cholesterol: below 200 mg/dL (about 5.2 mmol/L) desirable; 240 mg/dL (6.2 mmol/L) or more high.
LDL cholesterol: below 100 mg/dL (2.6 mmol/L) optimal; 160 mg/dL (4.1 mmol/L) or more high.
HDL cholesterol: below 40 mg/dL (1.0 mmol/L) low.
Triglycerides: below 150 mg/dL (1.7 mmol/L) normal.

Current guidelines set personal LDL targets according to overall cardiovascular risk, so your doctor may use a different goal.

Common mistakes

Using the cholesterol factor for triglycerides, which makes the mmol/L figure more than twice too high.
Rounding a mmol/L result to one decimal and converting back, which can shift mg/dL by a few units.
Comparing fasting and non-fasting triglyceride results as if they were equivalent.

Keep in mind: This is a unit conversion only, not a diagnosis or medical advice. Interpreting lipid levels depends on your age, other risk factors and the test method; discuss your results with a qualified health professional.

FAQ

Frequently asked questions

What is 150 mg/dL triglycerides in mmol/L?

150 ÷ 88.57 = 1.69 mmol/L.

What is 3.0 mmol/L LDL in mg/dL?

3.0 × 38.67 = 116 mg/dL.

Why is the factor 38.67 and not 38.6 on some charts?

Some references round the factor; the difference is under 0.2% and rarely matters.

Sources: NCEP Expert Panel, Third Report (Adult Treatment Panel III), NIH 2002 · IUPAC atomic weights (molar mass of cholesterol, C27H46O)

Unit conversion only — not medical advice.