# What is my cholesterol ratio?

Divides total cholesterol by HDL cholesterol (the Castelli index) and compares the ratio with the published risk level for men and for women.

- Page: https://www.acalculator.org/health/cholesterol-ratio-calculator
- JSON spec: https://www.acalculator.org/health/cholesterol-ratio-calculator.json
- Version: 021a0f6565ef

## Default answer

Example with the default inputs (Sex Male, Units mg/dL, Total cholesterol (mg/dL) 200, HDL cholesterol (mg/dL) 50): The total to HDL cholesterol ratio is 4: 5.0 or less, not above the risk level for men.

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| sex | Sex | The published risk levels differ for men and women. |
| units | Units | US units (mg/dL) or SI units (mmol/L). |
| tc | Total cholesterol (mg/dL) | Total cholesterol, 50 to 1,000 mg/dL. |
| tcSi | Total cholesterol (mmol/L) | Total cholesterol, 1.3 to 25.9 mmol/L. |
| hdl | HDL cholesterol (mg/dL) | HDL ("good") cholesterol, 5 to 200 mg/dL. |
| hdlSi | HDL cholesterol (mmol/L) | HDL ("good") cholesterol, 0.13 to 5.17 mmol/L. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| ratio | Total to HDL cholesterol ratio | Total cholesterol ÷ HDL cholesterol, to 1 decimal. |
| level | Risk level | Whether the ratio is above the primary-prevention risk level for the chosen sex (Millán 2009). |
| nonHdl | Non-HDL cholesterol (mg/dL) | Total cholesterol minus HDL cholesterol, in mg/dL, to a whole number. |
| nonHdlSi | Non-HDL cholesterol (mmol/L) | Total cholesterol minus HDL cholesterol, in mmol/L, to 2 decimals. |

## Method

Ratio = total cholesterol ÷ HDL cholesterol (same units), to 1 decimal. Risk level (Millán 2009, Table 1, primary prevention): over 5.0 for men, over 4.5 for women.

## Assumptions

- Total and HDL cholesterol come from the same blood sample.
- The ratio is rounded once to 1 decimal, halves away from zero, and the shown value is compared with the risk level.

## Worked examples

1. sex = male, units = us, tc = 200, hdl = 50 gives ratio = 4, level = 5.0 or less, not above the risk level for men, nonHdl = 150, nonHdlSi = 3.88. Source: Millán et al. 2009, Table 1, men over 5.0.
2. sex = male, units = us, tc = 220, hdl = 40 gives ratio = 5.5, level = Above 5.0, the risk level for men, nonHdl = 180. Source: 220 ÷ 40 = 5.5, over 5.0 (Millán et al. 2009, Table 1).
3. sex = female, units = us, tc = 190, hdl = 42 gives ratio = 4.5, level = 4.5 or less, not above the risk level for women. Source: Women over 4.5 (Millán et al. 2009, Table 1).
4. sex = female, units = us, tc = 220, hdl = 40 gives ratio = 5.5, level = Above 4.5, the risk level for women. Source: 220 ÷ 40 = 5.5, over 4.5 (Millán et al. 2009, Table 1) ().
5. sex = female, units = si, tcSi = 5.2, hdlSi = 1.3 gives ratio = 4, nonHdlSi = 3.9, nonHdl = 151.

## FAQ

### How do I calculate my cholesterol ratio?

Divide total cholesterol by HDL cholesterol. Both must be in the same units. 200 mg/dL ÷ 50 mg/dL gives a ratio of 4.0. The ratio is the same in mg/dL and mmol/L.

### What is a good cholesterol ratio?

Millán et al. (2009) list a ratio over 5.0 for men and over 4.5 for women as the risk level for people without heart disease.

### Why does the ratio matter?

Kinosian et al. (1994) found that the total to HDL ratio predicted coronary heart disease better than total cholesterol or LDL cholesterol alone in three large US cohorts.

### Why are the levels different for men and women?

Millán et al. give separate levels for men and women, based on the studies they review. The level for women is lower.

### What is the Castelli index?

Another name for the total to HDL cholesterol ratio, after William Castelli of the Framingham Heart Study.

### What is non-HDL cholesterol?

Total cholesterol minus HDL cholesterol. The page shows it next to the ratio, in mg/dL and mmol/L.

## Sources

- Millán J, Pintó X, Muñoz A, et al. Lipoprotein ratios: physiological significance and clinical usefulness in cardiovascular prevention. Vasc Health Risk Manag. 2009;5:757-765. https://doi.org/10.2147/vhrm.s6269 (open at https://pmc.ncbi.nlm.nih.gov/articles/PMC2747394/, retrieved 2026-10-05)
- Kinosian B, Glick H, Garland G. Cholesterol and coronary heart disease: predicting risks by levels and ratios. Ann Intern Med. 1994;121(9):641-647. https://doi.org/10.7326/0003-4819-121-9-199411010-00002 (retrieved 2026-10-05)