LDL Cholesterol Calculator

Most labs do not measure LDL directly. They calculate it from your total cholesterol, HDL, and triglycerides. The classic Friedewald formula is LDL = total cholesterol minus HDL minus (triglycerides divided by 5), with all values in mg/dL. This calculator also runs the newer Martin-Hopkins equation, which replaces the fixed divisor of 5 with an adjustable factor based on your triglyceride and non-HDL levels.

Friedewald assumes everyone has the same triglyceride-to-VLDL ratio and divides triglycerides by a fixed 5. Martin-Hopkins instead picks a factor from a 180-cell table indexed by your non-HDL cholesterol and triglyceride level, so the VLDL estimate fits your panel more closely. Martin-Hopkins is generally more accurate, especially when LDL is low or triglycerides are above 150 mg/dL, where Friedewald tends to read too low.

Both the Friedewald and Martin-Hopkins equations were validated only for triglycerides below 400 mg/dL. Above that level the assumed relationship between triglycerides and VLDL breaks down, so any calculated LDL becomes unreliable. If your triglycerides reach 400 mg/dL, ask your lab for a direct LDL or beta-quantification measurement instead.

Using the NCEP ATP III bands, LDL below 100 mg/dL is optimal, 100 to 129 mg/dL is near optimal, 130 to 159 mg/dL is borderline high, 160 to 189 mg/dL is high, and 190 mg/dL or above is very high. Your personal target depends on your overall cardiovascular risk, so people with diabetes or existing heart disease are often advised to aim lower.

Non-HDL cholesterol is simply your total cholesterol minus your HDL, so it captures LDL plus VLDL and other atherogenic particles in one number. Because it does not rely on triglycerides at all, it stays accurate even when LDL cannot be calculated. Many guidelines now treat non-HDL as a co-primary target alongside LDL.

No. This calculator is for education only and is not a substitute for professional medical advice. Calculated LDL can differ from a direct lab measurement, and treatment depends on factors this tool does not consider, such as blood pressure, smoking, and family history. Always discuss your lipid results and any treatment with your healthcare provider.