Cholesterol Ratio Calculator
Cholesterol ratios put your lipid panel in proportion: instead of reading total cholesterol, HDL, and LDL in isolation, they express the balance between cholesterol being delivered to artery walls and cholesterol being carried away. Both ratios below come from the standard lipid panel you already have.
Total Cholesterol / HDL Ratio
Enter your value above to see the result.
LDL / HDL Ratio
The calculated LDL line on a standard panel is fine
Enter your value above to see the result.
This result is a screening estimate, not a diagnosis. Discuss your labs with a qualified healthcare professional.
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How it works
The formulas
TC/HDL-C ratio = total cholesterol ÷ HDL cholesterol. LDL/HDL ratio = LDL cholesterol ÷ HDL cholesterol. Because both values in each ratio carry the same unit, cholesterol ratios are unit-free: mmol/L values give exactly the same result as mg/dL (the 38.67 conversion factor cancels out).
What the ratios reflect
Total and LDL cholesterol track the atherogenic payload being delivered to artery walls; HDL tracks reverse transport back to the liver. The Framingham Heart Study popularized TC/HDL-C as one of the strongest single lipid predictors of coronary risk — stronger than total cholesterol alone.
Evidence level & limitations
The bands above are research-cohort conventions, not official guideline cut-offs — no major guideline issues formal ratio thresholds. Ratios summarize averages and do not replace ApoB, LDL particle number, or clinical context. Looking for triglycerides ÷ HDL instead? That is a different marker (an insulin-resistance signal) with its own TG/HDL Ratio Calculator page.
Frequently asked questions
How do I calculate my cholesterol ratio?
Take total cholesterol and divide by HDL cholesterol — both from the same standard lipid panel. Example: total cholesterol 200 mg/dL with HDL 50 mg/dL gives a ratio of 4.0. The calculator above does this instantly and adds the LDL/HDL view.
What is a good cholesterol ratio?
For TC/HDL-C, below 3.5 is considered optimal and below 5.0 desirable in population research. For LDL/HDL, below 2.0 is optimal and below 3.0 normal. These are research-cohort conventions rather than official guideline cut-offs.
What's the difference between the TC/HDL and TG/HDL ratios?
TC/HDL divides total cholesterol by HDL — an overall lipid-balance marker. TG/HDL divides triglycerides by HDL — more an insulin-resistance and LDL particle-size signal, calculated on our dedicated TG/HDL Ratio Calculator page. The two capture overlapping but distinct risk and often appear in the same searches.
My lab report is in mmol/L — do I need to convert?
No. Cholesterol ratios are unit-free: total, LDL, and HDL all convert with the same factor (×38.67 to mg/dL), so it cancels out. A ratio computed from mmol/L values is identical to one computed from mg/dL.
Is a high cholesterol ratio a diagnosis?
No. It is a screening signal computed from routine labs. A high ratio is a reason for a fuller workup — ApoB, triglycerides, fasting insulin, clinical context — not a diagnosis of any condition.
Sources
- Castelli WP, et al. Incidence of coronary heart disease and lipoprotein cholesterol levels: the Framingham Study. JAMA, 1986.
- Stampfer MJ, et al. A prospective study of cholesterol, apolipoproteins, and the risk of myocardial infarction. N Engl J Med, 1991.
This calculator is for informational purposes only and is not medical advice, diagnosis, or treatment. Reference ranges are general population guidelines — always discuss your lab results with a qualified healthcare professional.