LDL Calculated (Friedewald)
LDL (mg/dL) ≈ Total cholesterol − HDL − Triglycerides/5 (valid when fasting TG < 400 mg/dL in classic use).
Calculator
How it works
What this tool does
It applies the widely taught Friedewald equation used when direct LDL is unavailable and triglycerides are not markedly elevated.
Formula
LDL ≈ TC − HDL − TG/5 (TC, HDL, TG in mg/dL)
References
Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem. 1972;18(6):499-502.
Dosing & care
Teaching notes
- Martin-Hopkins and other modified equations improve accuracy in some populations with higher TG—this page uses classic Friedewald only.
- Non-fasting samples and very low LDL from PCSK9 therapy still require clinical interpretation.
Limitations
Inaccurate with hypertriglyceridemia, chylomicronemia, dysbetalipoproteinemia, and some postprandial states; direct LDL or advanced lipid testing may be required.
Lipid management (teaching)
- ASCVD risk calculators integrate more than LDL alone; follow current prevention guidelines.
- Secondary causes of dyslipidemia (thyroid, liver, nephrotic range proteinuria, medications) should be evaluated when results are discordant.
- Therapy decisions belong to the patient-clinician relationship—not this calculator.
Educational tool only—not for diagnosis or treatment decisions.