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Heart & Vascular

Total Cholesterol / HDL Ratio

The total cholesterol/HDL ratio divides total cholesterol by HDL, summarising your cholesterol balance in a single number.

What is Total Cholesterol / HDL Ratio?

The total/HDL ratio divides your total cholesterol by your HDL, summarising the balance between the two in a single number. A lower ratio is more favourable — it means a larger share of your cholesterol sits in the protective HDL fraction. The ratio is a quick summary, not a complete risk picture. Dutch and European guidelines have largely moved to non-HDL cholesterol and ApoB for estimating risk, because those count all the harmful particles more directly. The ratio remains useful for tracking changes over time.

Why is Total Cholesterol / HDL Ratio relevant?

The ratio is most useful for tracking your lipid profile over time. When LDL falls and HDL rises — the desired effect of better lifestyle or medication — the ratio improves twice as fast as the individual values, making your progress easy to see. The limitation is that the same ratio can arise in very different ways. A favourable ratio driven by a high HDL is not the same as the same ratio driven by a low total on medication. Without the individual values, you miss that context. For your actual risk, ApoB and LDL take precedence, with the ratio as a supplement.

Total Cholesterol / HDL Ratio high or low — what it means

With every ratio, always check the individual values of total cholesterol, LDL, HDL, and triglycerides — only then can you tell whether it reflects a genuinely favourable profile or a misleading one. A low ratio driven by an unexpectedly low HDL (from smoking, high triglycerides, or inactivity) is a warning, not reassurance. Non-HDL cholesterol and ApoB give a more accurate picture of your risk and are better suited as treatment targets. The ratio works well for tracking changes, but when there is doubt about your actual risk, the individual values — and especially ApoB — take precedence.

Total Cholesterol / HDL Ratio reference ranges

OptimalFavourable balance; lowest cardiovascular risk (NVKC: 'below 3.5 is best').< 3.5
AcceptableNVKC states the ratio should be below 5. There is often room to improve by raising HDL through exercise and lifestyle.3.5 - 5.0
ElevatedRaised cardiovascular risk; discuss with your GP and review the full lipid panel. For women a threshold around 4.5 is sometimes used.> 5.0

The total cholesterol/HDL ratio (total cholesterol divided by HDL, also called the Castelli index or atherogenic index) is unitless: you get the same value in mmol/L or mg/dL. It condenses the balance between 'bad' and 'good' cholesterol into a single number and is an aid to interpretation, not a stand-alone diagnosis. The cut-offs come from the NVKC laboratory guidance and international research (Framingham) and differ slightly between sources. Note: the Dutch NHG-Standaard CVRM (2024) no longer uses this ratio for formal risk scoring - it now relies on non-HDL cholesterol (total cholesterol minus HDL) and LDL. Always read the ratio alongside the individual values and your personal risk factors.

Educational information only — not medical advice. Consult a healthcare professional for clinical decisions.

Read about our scientific approach →Read the guide: Heart health →

Frequently asked questions

What is a normal total cholesterol/HDL ratio?

Below 3.5 is optimal and corresponds to the lowest cardiovascular risk. The NVKC considers a ratio under 5 still acceptable, but under 3.5 is best. A lower ratio is almost always more favourable. The cut-offs are reference points and differ slightly between sources, so always read your value against the range printed on your own result.

What does a high cholesterol ratio mean?

Above 5.0 is regarded as elevated cardiovascular risk; for women a threshold of around 4.5 is sometimes used. A high ratio means a larger share of your cholesterol sits in the harmful fraction relative to protective HDL. Discuss an elevated result with your GP and review the full lipid panel.

When is a cholesterol ratio concerning?

A ratio above 5.0 (for women sometimes around 4.5) signals elevated risk and warrants attention. Also watch for a seemingly low ratio driven by an unexpectedly low HDL (from smoking, high triglycerides, or inactivity) — that is a warning, not reassurance. For treatment, modern Dutch (NHG) and European guidelines steer mainly on non-HDL cholesterol, LDL, and ApoB, so always interpret the ratio together with your individual values and your doctor.

How do I calculate my cholesterol ratio?

Divide your total cholesterol by your HDL cholesterol. For example, 6.0 divided by 2.0 is 3.0 - an excellent ratio. The result is unitless, so it is the same whether you measure in mmol/L or mg/dL. You only need total cholesterol and HDL; LDL and triglycerides are not required for the ratio itself.

How can I lower my cholesterol ratio?

The ratio often responds faster to raising HDL than to lowering total cholesterol. Regular aerobic exercise (about 150 minutes of moderate intensity per week), replacing saturated fat with olive oil, nuts and fish, more soluble fibre, stopping smoking, and reducing abdominal fat all improve the ratio. Expect three to six months before you see a clear change.

Related biomarkers

Total Cholesterol
Total cholesterol is the sum of all the cholesterol in your blood and the starting point of the lipid profile.
LDL Cholesterol
LDL cholesterol is the cholesterol in your blood that can lodge in artery walls and build up as plaque.
HDL Cholesterol
HDL is the 'good' cholesterol that carries excess cholesterol back to your liver.
Apolipoprotein B (ApoB)
ApoB is a protein on every harmful cholesterol particle, so it counts how many of those particles circulate in your blood.

Total Cholesterol / HDL Ratio is one of the biomarkers in the Optimize blood test. Book a blood draw at any of 238+ partner labs in the Netherlands, or upload your existing results in the app.

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