Total Cholesterol to HDL Ratio Calculator
Total Cholesterol to HDL Ratio Calculator
Divide total cholesterol by HDL cholesterol to get the Framingham risk ratio, read against sex-specific reference points — a risk marker rather than a treatment target.
Total Cholesterol to HDL Ratio
TC ÷ HDL → ratioTotal cholesterol 210 mg/dL, HDL cholesterol 48 mg/dL, male
Formula
- unit
- dimensionless — both terms are cholesterol, so the units cancel and the ratio is the same in mg/dL and mmol/L
- average risk
- 5.0 in men and 4.4 in women, the Framingham reference points for average coronary risk
- twice average
- 9.6 in men and 7.0 in women
Worked example
Total cholesterol 210 mg/dL, HDL cholesterol 48 mg/dL, male
210 ÷ 48 = 4.38
Below the male average reference point of 5.0 → average risk
The same values in mmol/L — 5.43 and 1.24 — give the same 4.38
Framingham reference points by sex
| Risk level | Men | Women |
|---|---|---|
| About half average | 3.4 | 3.3 |
| Average | 5.0 | 4.4 |
| Twice average | 9.6 | 7.0 |
Why two identical ratios can mean different things
| Total cholesterol | HDL | Ratio | Reading |
|---|---|---|---|
| 240 mg/dL | 48 mg/dL | 5.0 | High atherogenic burden with an average HDL |
| 150 mg/dL | 30 mg/dL | 5.0 | Low cholesterol with a markedly low HDL — often the metabolic syndrome |
What the ratio adds, and what it cannot do
The total cholesterol to HDL ratio is dimensionless. Both terms are cholesterol measured by the same assay principle, so the units cancel and the ratio is identical whether the report is in mg/dL or mmol/L. That is unusual among lipid calculations and makes the ratio one of the few numbers that can be compared directly between a laboratory in the United States and one in Europe without any conversion.
Its value is that it carries information LDL alone does not. Two people with the same LDL cholesterol but very different HDL levels have different risk, and the ratio expresses that in a single figure. It is most useful at the extremes: a person with a modest total cholesterol and an HDL of 28 mg/dL has an unfavourable ratio that an LDL result on its own would not convey, and a person with a high total cholesterol and an HDL of 90 mg/dL has a more reassuring one. The Framingham analyses used these reference points — an average ratio of 5.0 in men and 4.4 in women, with twice-average risk at 9.6 and 7.0 — precisely because the ratio graded risk better than either component alone.
It is a risk marker, not a treatment target. No major guideline sets a ratio goal, and treatment is directed at LDL cholesterol, non-HDL cholesterol or apolipoprotein B, none of which the ratio replaces. The reason is partly that the HDL term is not modifiable in a way that changes outcome: raising HDL pharmacologically, with niacin or with cholesteryl ester transfer protein inhibitors, has repeatedly failed to reduce cardiovascular events even when it moved the ratio in the right direction.
The ratio also hides what produced it. A ratio of 5.0 from a total cholesterol of 240 and an HDL of 48 describes a different patient from a ratio of 5.0 from a total of 150 and an HDL of 30, and the two need different management. The Framingham reference points come from a predominantly white cohort followed before statins were in routine use, so they describe untreated natural history rather than risk on treatment. Read the ratio next to the values it came from, and let a formal absolute risk estimate drive the decision.
Frequently asked questions
What is a good total cholesterol to HDL ratio?
Around 3.4 in men and 3.3 in women is roughly half the Framingham average risk. The average reference points are 5.0 for men and 4.4 for women, and twice-average risk sits at 9.6 and 7.0 respectively.
Does the ratio change between mg/dL and mmol/L?
No. Both terms are cholesterol and convert with the same factor, so the units cancel. A ratio calculated in mg/dL is identical to the one calculated in mmol/L, provided both values use the same unit.
Is the cholesterol ratio better than LDL?
It is not better, but it adds information when HDL is very low or very high, which LDL alone does not capture. Treatment decisions are still made on LDL, non-HDL or apolipoprotein B.
Is there a guideline target for the cholesterol ratio?
No. It is used as a risk marker rather than a treatment target, in part because raising HDL with drugs has not been shown to reduce cardiovascular events even when the ratio improves.
Related calculators
References
- Castelli WP. Cholesterol and lipids in the risk of coronary artery disease — the Framingham Heart Study. Can J Cardiol. 1988;4(Suppl A):5A–10A.
- 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.
- Grundy SM, Stone NJ, Bailey AL, et al. 2018 AHA/ACC multisociety guideline on the management of blood cholesterol. Circulation. 2019;139(25):e1082–e1143.