Cholesterol Ratio Calculator

Cholesterol ratios provide a more nuanced picture of cardiovascular risk than any single cholesterol number. The two most clinically useful ratios are the Total Cholesterol to HDL ratio and the LDL to HDL ratio.

Formulas:

Total Cholesterol to HDL Ratio: TC/HDL = Total Cholesterol ÷ HDL Cholesterol

LDL to HDL Ratio: LDL/HDL = LDL Cholesterol ÷ HDL Cholesterol

Calculated LDL (Friedewald Equation — used when LDL is not measured directly): LDL = Total Cholesterol − HDL − (Triglycerides ÷ 5) (valid only when triglycerides < 400 mg/dL)

Non-HDL Cholesterol (includes all atherogenic particles): Non-HDL = Total Cholesterol − HDL

What each variable means:

• Total Cholesterol (TC) — sum of all cholesterol types in your blood.
• HDL — “good” cholesterol; higher is better; removes cholesterol from arteries.
• LDL — “bad” cholesterol; deposits in artery walls; lower is better.
• Triglycerides — a type of fat in the blood; elevated by sugar and alcohol intake.

Reference ranges (mg/dL):

• TC/HDL ratio: Optimal < 3.5 | Acceptable < 5.0 | High risk > 5.0
• LDL/HDL ratio: Optimal < 2.0 | Acceptable < 3.0 | High risk > 3.5
• HDL: Low risk > 60 | Acceptable 40–60 | High risk < 40 (men), < 50 (women)

Worked example: Blood panel: TC = 210, HDL = 58, Triglycerides = 120. LDL = 210 − 58 − (120 ÷ 5) = 210 − 58 − 24 = 128 TC/HDL = 210 ÷ 58 = 3.62 (acceptable range) LDL/HDL = 128 ÷ 58 = 2.21 (acceptable range)

Note: Always interpret cholesterol ratios alongside your doctor’s full cardiovascular risk assessment.