What this calculator does
The total cholesterol to HDL ratio compresses a lipid panel into one number. Because HDL sits in the denominator, raising it improves the ratio just as much as lowering total cholesterol does.
That is the useful part. A total of 200 mg/dL looks identical on a report whatever the HDL, but against an HDL of 40 the ratio is 5.0 to 1 and against an HDL of 65 it is 3.1 to 1, which are quite different pictures.
The formula
Divide total cholesterol by HDL cholesterol. Both must be in the same units, so the result is a plain ratio.
| Term | Meaning |
|---|---|
| Cholesterol ratio | Total cholesterol divided by HDL. |
| HDL | High density lipoprotein, associated with lower cardiovascular risk. |
| Commonly cited target | Below 5 to 1, with around 3.5 to 1 often described as favourable. |
The inputs explained
| Field | What to enter |
|---|---|
| Total cholesterol (mg/dL) | Total cholesterol in mg/dL. |
| HDL cholesterol (mg/dL) | HDL cholesterol in mg/dL. |
When to use it
Summarising a lipid panel
One ratio is easier to track over time than four separate values.
Seeing the effect of raising HDL
Exercise and dietary changes that lift HDL improve the ratio without touching total cholesterol.
Comparing results over time
The ratio is less sensitive than LDL to whether the sample was fasting.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How much does HDL change the ratio?
The same total cholesterol at three HDL levels.
| HDL cholesterol | Cholesterol ratio | Commonly cited target |
|---|---|---|
| 40 mg/dL | 5.0:1 | below 5:1, ideally near 3.5:1 |
| 50 mg/dL | 4.0:1 | below 5:1, ideally near 3.5:1 |
| 65 mg/dL | 3.1:1 | below 5:1, ideally near 3.5:1 |
Questions
Is the ratio better than looking at LDL?
It is a different summary rather than a better one. The ratio captures the balance between the two, while LDL is what most treatment guidelines are written against. Clinicians generally look at both along with the rest of the panel.
Can a good ratio hide a problem?
Yes. A very high HDL can produce a reassuring ratio while LDL is also high, and that combination still warrants attention. No single number substitutes for reading the whole panel.
How do I improve the ratio?
Both directions help, and the usual measures act on both: regular physical activity, not smoking, and dietary changes. What is appropriate for you specifically is a conversation to have with your doctor.
Does the ratio predict risk on its own?
No. Cardiovascular risk depends on blood pressure, smoking, diabetes, age, family history and more, and formal risk scores combine all of them. The ratio is one input among many.
For the LDL figure from the same panel, see the LDL cholesterol calculator. For average circulatory pressure, see the mean arterial pressure calculator.