Cholesterol Ratio Calculator
Work out your total cholesterol to HDL ratio, a quick marker of heart risk.
What is the cholesterol ratio?
The cholesterol ratio is your total cholesterol divided by your HDL cholesterol. HDL is the "good" cholesterol that helps clear fat from your arteries, so dividing your total by it gives a single number that reflects the balance between harmful and protective cholesterol. A lower ratio is better.
Why the ratio beats total cholesterol alone
Total cholesterol on its own can be misleading. Two people with a total of 200 mg/dL can carry very different risk: one with high protective HDL, the other with high harmful LDL. The ratio exposes that difference, which is why it often predicts heart risk better than the total figure on its own. Because it is a ratio, the units cancel out, so it reads the same whether your lab uses mg/dL or mmol/L.
What your result means
| Ratio | Interpretation |
|---|---|
| Below 3.5 | Optimal |
| 3.5 to 5.0 | Borderline / moderate risk |
| Above 5.0 | High risk |
These are general bands. Women tend to have higher HDL and slightly different reference points, and the ratio is only one piece of the picture - your LDL, triglycerides, blood pressure, blood sugar, smoking status and family history all matter.
How to improve it
You can move the ratio down from both ends: raise HDL with regular physical activity, and lower LDL and triglycerides through diet, weight loss and, where your doctor advises it, medication. Recheck after a few months of changes rather than reacting to a single reading.
Frequently asked questions
What is the cholesterol ratio?
It is your total cholesterol divided by your HDL ("good") cholesterol - a single number that captures the balance between harmful and protective cholesterol.
Why is the ratio more useful than total cholesterol alone?
Two people can share the same total cholesterol but very different risk. The ratio reveals whether that total is driven by harmful cholesterol or by protective HDL, so it tracks risk better than the total on its own.
What is a good cholesterol ratio?
Generally, below 3.5 is optimal and above 5 signals higher risk. Lower is better. Your doctor reads it alongside LDL, triglycerides and your other risk factors.
Does the ratio differ for men and women?
Women tend to have higher HDL, so reference points differ slightly by sex. The number is best interpreted within your overall cardiovascular risk, not in isolation.
How can I improve my ratio?
Regular activity raises HDL, while a better diet, weight loss and (when prescribed) medication lower LDL and triglycerides. Both directions improve the ratio.
Formula source: Millan J et al. Lipoprotein ratios: physiological significance and clinical usefulness. Vasc Health Risk Manag 2009;5:757-765.
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