How is LDL cholesterol calculated using the Friedewald equation?
The Friedewald equation estimates LDL as: LDL = Total Cholesterol − HDL − (Triglycerides ÷ 5). The triglycerides ÷ 5 portion estimates VLDL cholesterol. This formula was developed in 1972 and is the most widely used method in clinical labs worldwide. See also our ASCVD Risk Calculator.
What is a normal LDL cholesterol level?
According to standard guidelines: below 100 mg/dL is optimal, 100–129 mg/dL is near optimal, 130–159 mg/dL is borderline high, 160–189 mg/dL is high, and 190 mg/dL or above is very high. Your target LDL may be lower (e.g. below 70 mg/dL) if you have heart disease or diabetes — always consult your doctor.
How do I calculate LDL with total cholesterol 230, HDL 47, and triglycerides 123?
Using the Friedewald equation: LDL = 230 − 47 − (123 ÷ 5) = 230 − 47 − 24.6 = 158.4 mg/dL. This falls in the 'borderline high' category and should be discussed with a healthcare provider.
How do I calculate total cholesterol from LDL and HDL?
Total cholesterol = LDL + HDL + VLDL (where VLDL ≈ Triglycerides ÷ 5). So if you know your LDL, HDL, and triglycerides, you can rearrange the formula: TC = LDL + HDL + (TG ÷ 5). You might also find our use the Cholesterol Ratio Calculator useful.
Are there limitations to the Friedewald equation?
Yes. The Friedewald equation is considered inaccurate when triglycerides exceed 400 mg/dL, in patients with type III hyperlipoproteinemia, or when chylomicrons are present (e.g. non-fasting samples). In these cases, direct LDL measurement is recommended. This calculator will flag values above 400 mg/dL.
How do I lower my LDL below 70 mg/dL?
Achieving LDL below 70 mg/dL typically requires a combination of dietary changes (reducing saturated and trans fats), regular aerobic exercise, and often statin medications. For very high-risk patients, additional therapies like PCSK9 inhibitors or ezetimibe may be prescribed by a cardiologist.
What is the difference between LDL and non-HDL cholesterol?
Non-HDL cholesterol includes all cholesterol carried by atherogenic (artery-clogging) particles — LDL, VLDL, IDL, and lipoprotein(a). It is calculated as Total Cholesterol − HDL. Non-HDL is considered a better predictor of cardiovascular risk than LDL alone, and its optimal level is generally 30 mg/dL higher than the target LDL.
Do I need to fast before a cholesterol test for this calculation to be valid?
Fasting (typically 9–12 hours) is traditionally recommended before a lipid panel because eating raises triglyceride levels, which affects the Friedewald LDL estimate. Many labs now perform non-fasting lipid panels, but the Friedewald formula is most accurate on fasting samples with triglycerides below 400 mg/dL.