THE NUMORIX GUIDE
How to use the Cholesterol Ratio Calculator
Last reviewed September 14, 2026
What this calculator does
The engine divides total cholesterol by HDL to produce TC/HDL and LDL by HDL to produce LDL/HDL, rounding each to two decimals.
Formula and method
The engine divides total cholesterol by HDL to produce TC/HDL and LDL by HDL to produce LDL/HDL, rounding each to two decimals. It interprets only TC/HDL: below 3.5 is optimal, below 5 borderline, below 7 high, and 7 or higher very high.
Variables and inputs
Total cholesterol, HDL, LDL, and triglycerides are entered in mg/dL. HDL is the denominator for both ratios, so it must be nonzero for a meaningful result. Although triglycerides appear in the form, the current engine does not use them in either calculation or interpretation.
Worked example
For total 220, HDL 55, LDL 140, and triglycerides 150 mg/dL: TC/HDL = 220 / 55 = 4.00; LDL/HDL = 140 / 55 = 2.55 after rounding; TC/HDL is interpreted as borderline. The triglyceride input does not change that output.
How to interpret the result
A ratio summarizes the relationship between selected lipid values. It should be read alongside the raw total, LDL, HDL, triglycerides, personal risk factors, and treatment goals rather than used as a stand-alone health grade.
Common mistakes to avoid
Use HDL as the denominator exactly as the engine does, keep all values in mg/dL, and do not expect triglycerides to affect this route. Do not compare a ratio from one lab panel with raw values from another without checking units and dates.
Assumptions and limitations
The engine does not validate zero or negative inputs, ignores triglycerides, uses fixed ratio bands, and does not model age, blood pressure, diabetes, smoking, family history, medications, or prior events. Ratio cutoffs are not a universal substitute for current clinical risk guidance.