Calculate your total cholesterol to HDL ratio and assess cardiovascular risk
This calculator is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.
Cholesterol is a fatty substance found in your blood that is essential for building cells, making hormones, and producing bile acids. However, having too much cholesterol -- particularly the wrong types -- significantly increases your risk of heart disease and stroke. Understanding your cholesterol ratio helps you assess your cardiovascular risk more accurately than looking at total cholesterol alone. The total cholesterol to HDL ratio is one of the most useful measures of cardiovascular risk. It compares your total cholesterol level to your HDL (high-density lipoprotein, often called "good" cholesterol) level. HDL cholesterol helps remove other forms of cholesterol from your bloodstream, so a higher proportion of HDL relative to total cholesterol indicates a healthier profile. The NHS recommends a total:HDL ratio below 4, with an ideal ratio below 3. This calculator computes your total:HDL ratio, non-HDL cholesterol, and optionally estimates your LDL cholesterol using the Friedewald equation. It categorises your cardiovascular risk based on established clinical thresholds used by the NHS and the British Heart Foundation.
To calculate your cholesterol ratio: 1. Enter your total cholesterol level in mmol/L. This is the combined measure of all types of cholesterol in your blood. The NHS considers a total cholesterol of 5 mmol/L or below as healthy, though the ratio matters more than the total alone. 2. Enter your HDL cholesterol level in mmol/L. This is your "good" cholesterol. An HDL level above 1 mmol/L for men or 1.2 mmol/L for women is considered healthy by the NHS. Higher is generally better. 3. Optionally enter your LDL cholesterol in mmol/L. If you do not know your LDL level, leave it at 0 and optionally provide your triglycerides level instead -- the calculator will estimate your LDL using the Friedewald equation. 4. Optionally enter your triglycerides level in mmol/L. This is used to estimate LDL if not directly provided. A healthy fasting triglyceride level is below 1.7 mmol/L according to the NHS. 5. Review your results. The calculator shows your total:HDL ratio, risk category, non-HDL cholesterol, and whether you meet the NHS target of a ratio below 4.
The total cholesterol to HDL ratio is calculated by dividing your total cholesterol by your HDL cholesterol: Total:HDL Ratio = Total Cholesterol / HDL Cholesterol For example, if your total cholesterol is 5.0 mmol/L and your HDL is 1.5 mmol/L, your ratio is 5.0 / 1.5 = 3.3 (desirable). Non-HDL cholesterol is calculated simply as: Non-HDL = Total Cholesterol - HDL Cholesterol. The NHS recommends a non-HDL cholesterol below 4 mmol/L. If LDL cholesterol is not directly measured but triglycerides are available, the calculator uses the Friedewald equation to estimate LDL: LDL = Total Cholesterol - HDL - (Triglycerides / 2.2). This estimation is widely used in clinical practice but is less accurate when triglycerides are very high (above 4.5 mmol/L). Risk categories based on total:HDL ratio are: Optimal (below 3), Desirable (3 to 4), Borderline high (4 to 5), and High risk (above 5). These thresholds are based on epidemiological data linking cholesterol ratios to cardiovascular event rates.
Cholesterol levels are typically measured through a blood test called a lipid profile or lipid panel. The NHS recommends that adults over 40 should have their cholesterol checked as part of an NHS Health Check. You may need to fast for 12 hours before the blood test for the most accurate triglyceride measurement. If your cholesterol ratio is above the NHS target of 4, your GP may recommend lifestyle changes such as eating less saturated fat, exercising more, losing weight, and stopping smoking. If these changes are not sufficient, statins may be prescribed. Statins are the most commonly prescribed medication for high cholesterol in the UK and have been shown to significantly reduce cardiovascular risk. Reference: NHS Cholesterol levels guidance (nhs.uk/conditions/high-cholesterol), British Heart Foundation cholesterol information (bhf.org.uk), NICE Cardiovascular risk assessment guideline CG181.