π©Έ LDL Cholesterol Calculator
Friedewald LDL from your lipid panel.
For informational purposes only, not medical advice. Consult a healthcare professional.
LDL cholesterol is usually calculated, not measured directly. The Friedewald equation subtracts HDL and an estimate of VLDL (triglycerides divided by 5) from total cholesterol, leaving LDL. It has been the clinical standard since 1972 because it is cheap, fast, and accurate whenever triglycerides are under 400 mg/dL.
Enter total cholesterol, HDL, and triglycerides in mg/dL. The calculator returns LDL plus non-HDL cholesterol, which many cardiologists now track as the more complete risk number, and flags when triglycerides invalidate the formula.
How to Use This Calculator
Copy the three numbers from your lipid panel: total cholesterol, HDL, and triglycerides, all in mg/dL. Ideally the sample was fasting 9 to 12 hours, since non-fasting triglycerides skew the math. Read LDL, check the validity flag, and compare against the ATP III bands.
Enter total cholesterol, HDL, and triglycerides from your lipid panel.
Check the validity flag: triglycerides must be under 400 mg/dL.
Read LDL and non-HDL cholesterol.
Compare against target bands and discuss with your doctor.
The Friedewald Equation
Valid when TG < 400 mg/dL
Total cholesterol is the sum of LDL, HDL, and VLDL. VLDL carries most circulating triglycerides at a roughly 5-to-1 mass ratio, so TG/5 estimates VLDL cholesterol, and the subtraction isolates LDL. The ratio breaks down when triglycerides are very high because chylomicrons appear and the 5-to-1 assumption fails; above 400 mg/dL the equation can underestimate LDL substantially. Newer equations (Martin-Hopkins, Sampson) use adjustable ratios and stay accurate at higher triglycerides, and many labs now report those or direct LDL instead.
Worked Example
Total 220, HDL 55, triglycerides 150: LDL comes out 135 mg/dL, in the Borderline high band, with non-HDL at 165 mg/dL. Push triglycerides to 450 and the calculator flags Yes: TG < 400: Friedewald underestimates LDL badly when triglycerides run high, and labs switch to direct measurement.
Reading Your LDL Band
ATP III bands: under 100 optimal, 100-129 near optimal, 130-159 borderline high, 160-189 high, 190+ very high. Targets tighten with risk: under 100 for most, under 70 for established heart disease or very high risk. But LDL is one risk factor among several: blood pressure, smoking, diabetes, age, and family history all feed the 10-year ASCVD risk that actually drives statin decisions. Non-HDL cholesterol (total minus HDL) deserves equal attention; it captures all atherogenic particles and predicts risk slightly better than LDL alone.
| LDL (mg/dL) | Band | Typical target |
|---|---|---|
| <100 | Optimal | General goal |
| 100-129 | Near optimal | |
| 130-159 | Borderline high | Lifestyle + evaluate |
| 160-189 | High | Often medication |
| 190+ | Very high | Medication likely |
Numbers Guide, Doctors Decide
Statin decisions rest on overall cardiovascular risk, not LDL alone: a 45-year-old non-smoker at 165 and a 65-year-old diabetic smoker at 135 need very different plans. Very high LDL (190+) can signal familial hypercholesterolemia, which deserves dedicated evaluation and family screening. Bring the full lipid panel and your history to your doctor rather than treating one number. For informational purposes only, not medical advice. Consult a healthcare professional.
Related tools: metabolic syndrome checker, mmol/L to mg/dL converter and blood pressure checker.
For informational purposes only, not medical advice. Consult a healthcare professional.
Frequently Asked Questions
How is LDL calculated?
With the Friedewald equation: total cholesterol minus HDL minus triglycerides divided by 5. It is valid when triglycerides are under 400 mg/dL.
What is a good LDL level?
Under 100 mg/dL is optimal for most adults; under 70 for people with established heart disease or very high risk.
Why does my lab report differ from Friedewald?
Many labs now use the Martin-Hopkins or Sampson equations, which stay accurate at higher triglycerides, or measure LDL directly. Small differences are normal.
What is non-HDL cholesterol?
Total cholesterol minus HDL: all the atherogenic particles in one number. Many cardiologists consider it the better risk predictor.
Do I need to fast before a lipid panel?
Fasting 9 to 12 hours gives the most accurate triglycerides and Friedewald LDL. Many clinics now accept non-fasting samples and use newer equations.
Can LDL be too low?
Very low LDL on statins has not shown harm in trials, and lower generally means lower risk. Naturally very low LDL is rare and usually benign.
How fast can diet lower LDL?
Meaningful dietary changes typically move LDL 5 to 15% over 6 to 12 weeks. Soluble fiber, plant sterols, and cutting saturated fat do most of the work.
What raises triglycerides the most?
Excess alcohol, sugary drinks, refined carbs, and uncontrolled diabetes. High triglycerides also break the Friedewald calculation.
Why does the Friedewald formula fail when triglycerides are high?
The formula assumes a fixed ratio of triglycerides to VLDL cholesterol, roughly 5 to 1, which holds only when triglycerides are under 400 mg per dL. Above that, chylomicrons and abnormal VLDL break the assumption, and the calculation can understate LDL badly. Direct LDL measurement or the newer Martin-Hopkins equation handles high triglycerides better.
Is non-HDL cholesterol a better number to watch than LDL?
Many cardiologists now say yes. Non-HDL (total minus HDL) captures every atherogenic particle, including VLDL and remnants that Friedewald LDL misses, and it needs no fasting sample. Guidelines still set LDL targets, but non-HDL is a strong second target, usually set 30 mg per dL above the LDL goal.