Leave 0 to compute via Friedewald
Input total cholesterol from your lab report.
Provide HDL (high-density lipoprotein).
Input LDL if measured, or leave 0 to calculate via Friedewald.
Provide triglycerides.
Review LDL, non-HDL, ratios, and category for each value.
The Friedewald equation estimates LDL when it's not directly measured. It assumes triglycerides and VLDL are in a fixed ratio, which breaks down when triglycerides exceed 400 mg/dL. Non-HDL cholesterol is increasingly used because it captures all atherogenic lipoproteins (LDL + VLDL + IDL + Lp(a)) and is reliable even with high triglycerides. NCEP ATP III categories are the standard framework for interpreting lipid values.
LDL (Friedewald) = Total − HDL − Triglycerides/5 (valid if TG < 400)
Total cholesterol: <200 desirable, 200-239 borderline, ≥240 high
LDL: <100 optimal, 100-129 near optimal, 130-159 borderline, 160-189 high, ≥190 very high
HDL: <40 low (risk factor), 40-59 average, ≥60 protective
Triglycerides: <150 normal, 150-199 borderline, 200-499 high, ≥500 very high
Non-HDL = total − HDL is more reliable than LDL when triglycerides are elevated
Total/HDL ratio under 3.5 is desirable; under 5 is acceptable
Lifestyle (Mediterranean diet, exercise, weight loss) can drop LDL by 20-30%
Cholesterol testing is one of the most commonly ordered blood panels, with the American Heart Association recommending screening every 4-6 years for adults over 20. A standard lipid panel reports total cholesterol, HDL (good cholesterol), LDL (bad cholesterol), and triglycerides — but interpreting these numbers requires context. Optimal LDL is below 100 mg/dL, while HDL above 60 mg/dL is considered cardio-protective. The total cholesterol to HDL ratio is a powerful predictor of cardiovascular risk: a ratio below 3.5 is ideal, while above 5.0 signals elevated risk. Many labs report only total cholesterol, HDL, and triglycerides, requiring LDL to be calculated using the Friedewald equation: LDL equals total cholesterol minus HDL minus triglycerides divided by 5. This formula is reliable when triglycerides are below 400 mg/dL. This cholesterol calculator takes your lipid panel values, computes LDL if not provided, calculates all clinically relevant ratios including total/HDL, LDL/HDL, and triglyceride/HDL, then classifies each metric against established guidelines from the ATP III and AHA frameworks. Use it to track your lipid health between doctor visits.
A 'good' cholesterol report needs all four metrics in healthy ranges, not just total cholesterol. Two people can have identical total cholesterol of 200 but very different cardiovascular risk depending on their HDL and triglycerides. High HDL with moderate LDL is much safer than low HDL with the same LDL. Modern guidelines emphasize the full panel and derived metrics like non-HDL and the total/HDL ratio over total cholesterol alone.
The Friedewald equation assumes a fixed ratio of triglycerides to VLDL cholesterol. This works well when triglycerides are below 400 mg/dL, which covers the vast majority of patients. Above 400, the equation overestimates VLDL and underestimates LDL. In those cases, labs use direct LDL measurement or non-HDL cholesterol as the primary metric. If your triglycerides are above 400, prefer the directly measured LDL or non-HDL value.
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All formulas verified against official standards.