LDL Cholesterol Calculator (Friedewald)

About this calculator

This calculator applies the Friedewald equation, LDL = Total Cholesterol − HDL − Triglycerides/5, published in 1972 by Friedewald, Levy and Fredrickson as a way to estimate LDL cholesterol without the cost and complexity of direct ultracentrifugation. The TG/5 term approximates VLDL cholesterol from triglycerides, since VLDL particles normally carry roughly one-fifth of their cholesterol content as triglyceride under fasting conditions.

Clinical laboratories and physicians rely on this formula for routine lipid panels because it turns three cheaply measured values — total cholesterol, HDL and triglycerides — into the LDL figure used for cardiovascular risk stratification and statin therapy decisions. The estimate is only valid on a fasting sample with triglycerides below roughly 400 mg/dL, since the fixed VLDL ratio breaks down at higher triglyceride levels; direct LDL measurement or the Martin-Hopkins method is preferred outside that range.