Cholesterol Unit Converter
Cholesterol Unit Converter
Convert total, LDL and HDL cholesterol between mg/dL, mg/L, g/L and mmol/L — and see why the triglyceride on the same report needs a different factor entirely.
Cholesterol converter
Mass ⇄ molarTotal cholesterol 190 mg/dL
Formula and conversion factor
mg/dL = mmol/L × 38.67
- 0.0259
- derived from the molecular weight of cholesterol, 386.65 Da: 1 mg/dL is 0.01 g/L, and 0.01 ÷ 386.65 mol/L is 0.0259 mmol/L
- total, LDL, HDL
- all three are cholesterol mass, so all three use the same factor
- triglycerides
- a different molecule — conventionally taken as triolein, 885.4 Da — and a different factor of 0.0113; never convert a triglyceride with the cholesterol factor
- g/L
- occasionally used in continental European reports; 1 g/L is 100 mg/dL
Worked example
Total cholesterol 190 mg/dL
190 × 0.0259 = 4.91 mmol/L
= 1900 mg/L = 1.900 g/L
Below the conventional desirable limit of 200 mg/dL (5.17 mmol/L), so this sits inside the desirable range
Common cholesterol values in both units
| Meaning | mg/dL | mmol/L |
|---|---|---|
| Anchor pair worth memorising | 200 | 5.17 |
| Desirable total cholesterol | < 200 | < 5.2 |
| Optimal LDL cholesterol | < 100 | < 2.6 |
| Very high risk LDL target | < 70 | < 1.8 |
| Very high LDL — consider familial hypercholesterolaemia | ≥ 190 | ≥ 4.9 |
| Low HDL cholesterol | < 40 | < 1.0 |
Cholesterol and triglyceride do not share a factor
| Analyte | Molecular weight | mg/dL → mmol/L | mmol/L → mg/dL |
|---|---|---|---|
| Cholesterol (total, LDL, HDL) | 386.65 Da | × 0.0259 | × 38.67 |
| Triglyceride (as triolein) | 885.4 Da | × 0.0113 | × 88.57 |
One factor for cholesterol, a different one for triglyceride
The conversion factor between mg/dL and mmol/L for cholesterol is 0.0259, and it comes directly from the molecular weight of cholesterol, 386.65 Da. A concentration of 1 mg/dL is 0.01 g/L; dividing that by 386.65 g/mol gives 2.59 × 10⁻⁵ mol/L, which is 0.0259 mmol/L. The reciprocal, 38.67, converts in the other direction. Nothing about the factor is empirical or assay-specific — it is arithmetic on a molecular weight.
The same factor applies to total, LDL and HDL cholesterol, and to non-HDL cholesterol as well, because all of them are measurements of cholesterol mass. The lipoprotein carrying the cholesterol does not change the molecule being measured, so there is no separate LDL factor or HDL factor to remember. This is worth stating explicitly, because the layout of a lipid report — with four numbers stacked in a column — invites the assumption that one factor converts the whole panel.
It does not, and this is the single most common conversion error on a lipid panel. Triglycerides are not cholesterol: they are conventionally treated as triolein, molecular weight 885.4 Da, which gives a factor of 0.0113 mmol/L per mg/dL and 88.57 in the reverse direction. Converting a triglyceride with the cholesterol factor overstates it by more than twofold — a triglyceride of 150 mg/dL becomes 3.9 mmol/L instead of 1.7, which turns a borderline result into one that looks like it needs urgent treatment. The same difference is why the Friedewald equation divides triglyceride by 5 in mg/dL but by 2.2 in mmol/L.
The one pair worth memorising is 200 mg/dL = 5.17 mmol/L, the conventional desirable limit for total cholesterol in both units; everything else can be scaled from it. A few more anchors make the conversion easy to sanity-check without a calculator: 100 mg/dL is about 2.6 mmol/L, 70 mg/dL is about 1.8 mmol/L, and 40 mg/dL is about 1.0 mmol/L. Roughly, mmol/L is mg/dL divided by 40. Conversion changes nothing about the biology or the clinical meaning of a result, but a lipid value quoted without its unit is genuinely ambiguous, and reading 5.2 as mg/dL rather than mmol/L, or the reverse, is a real source of error when reports move between countries.
Frequently asked questions
How do I convert cholesterol from mg/dL to mmol/L?
Multiply by 0.0259, or divide by 38.67. A total cholesterol of 200 mg/dL is 5.17 mmol/L. The same factor applies to total, LDL and HDL cholesterol.
Is the conversion factor the same for LDL and HDL cholesterol?
Yes. All three are measurements of cholesterol mass, so all three use the factor derived from the molecular weight of cholesterol, 386.65 Da.
Can I use the same factor for triglycerides?
No, and this is the commonest error on a lipid panel. Triglyceride is conventionally taken as triolein at 885.4 Da, giving a factor of 0.0113. Using the cholesterol factor overstates a triglyceride by more than twofold.
What is a total cholesterol of 5.2 mmol/L in mg/dL?
About 200 mg/dL, which is the conventional upper limit of a desirable total cholesterol. Multiply mmol/L by 38.67 to convert in that direction.
Why do some European reports use g/L?
It is an alternative mass unit used in parts of continental Europe. One g/L is 100 mg/dL, so a total cholesterol of 2.00 g/L is 200 mg/dL, or 5.17 mmol/L.
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References
- Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. Third Report of the National Cholesterol Education Program (NCEP) Expert Panel (Adult Treatment Panel III) final report. Circulation. 2002;106(25):3143–3421.
- Rifai N, Horvath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018.
- Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem. 1972;18(6):499–502.
Medical Disclaimer: The tools and content provided here are for educational and reference purposes only. They are not intended to substitute for professional medical advice, diagnosis, or treatment. Clinical decisions should always be based on the comprehensive assessment of a qualified healthcare professional.