LDL Calculator
Calculate your LDL cholesterol level using the Friedewald formula. Get instant VLDL, non-HDL cholesterol, TC/HDL ratio, and cardiovascular risk category from your lipid panel results.
About This Calculator
The LDL Cholesterol Calculator estimates your low-density lipoprotein (LDL) cholesterol using the internationally recognized Friedewald equation, developed by W.T. Friedewald, R.I. Levy, and D.S. Fredrickson in 1972. This method is the standard clinical approach for estimating LDL from a routine lipid panel without requiring direct ultracentrifugation measurement.
LDL cholesterol, often called "bad cholesterol," is a critical marker for cardiovascular disease risk assessment. High levels of LDL promote atherosclerosis — the buildup of plaque in arterial walls — increasing the risk of heart attack, stroke, and peripheral artery disease. The calculator also provides VLDL (very-low-density lipoprotein), non-HDL cholesterol, and the TC/HDL ratio for a comprehensive lipid assessment.
How it works: The Friedewald equation calculates LDL as: LDL = Total Cholesterol − HDL − (Triglycerides / 5) when using mg/dL units, or LDL = Total Cholesterol − HDL − (Triglycerides / 2.22) for mmol/L. VLDL is estimated as Triglycerides / 5 (mg/dL) or Triglycerides / 2.22 (mmol/L). Non-HDL cholesterol equals total cholesterol minus HDL. The TC/HDL ratio is total cholesterol divided by HDL.
Regional Guidelines
India: The Cardiological Society of India (CSI) recommends LDL targets based on risk stratification. For high-risk patients (established CVD, diabetes, or familial hypercholesterolemia), LDL should be below 70 mg/dL. For moderate-risk patients, below 100 mg/dL is advised. Lipid profile testing is recommended every 5 years for adults over 20, and more frequently for those with risk factors.
United States: The ACC/AHA guidelines recommend statin therapy based on 10-year ASCVD risk score rather than LDL targets alone. However, LDL < 100 mg/dL is considered optimal, and LDL < 70 mg/dL is recommended for very high-risk patients (clinical ASCVD). The ATP III classification remains widely used for LDL categorization.
United Kingdom: NICE guidelines (CG181) recommend assessing CVD risk using QRISK3. Statin therapy is offered to adults with a 10-year risk of 10% or more. LDL targets are typically below 3.0 mmol/L (116 mg/dL) for primary prevention and below 1.8 mmol/L (70 mg/dL) for secondary prevention. Total cholesterol should be below 4.0 mmol/L (155 mg/dL) for secondary prevention.
Limitations: The Friedewald equation is most accurate for fasting lipid panels with triglycerides below 400 mg/dL (4.5 mmol/L). It becomes less reliable in non-fasting samples, very high or very low triglyceride levels, and in patients with type I or III hyperlipoproteinemia. Direct LDL measurement is recommended in these cases.
Frequently Asked Questions
How is LDL cholesterol calculated using the Friedewald equation?
LDL cholesterol is estimated using the Friedewald equation: LDL = Total Cholesterol - HDL - (Triglycerides / 5) when values are in mg/dL, or LDL = Total Cholesterol - HDL - (Triglycerides / 2.22) for mmol/L. The result is an indirect estimate based on a standard lipid panel, not a direct measurement.
What are the normal LDL cholesterol levels by risk category?
According to ESC/EAS guidelines, LDL cholesterol levels are categorized as: Optimal — below 100 mg/dL (2.6 mmol/L); Near Optimal — 100-129 mg/dL (2.6-3.3 mmol/L); Borderline High — 130-159 mg/dL (3.4-4.1 mmol/L); High — 160-189 mg/dL (4.1-4.9 mmol/L); Very High — 190 mg/dL and above (4.9 mmol/L and above). The target depends on individual cardiovascular risk factors.
Can I rely on this calculator for medical diagnosis?
No. This calculator is for educational and reference purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a healthcare professional for interpretation of your lipid panel results.
When is the Friedewald equation inaccurate?
The Friedewald equation has limitations. It becomes inaccurate when triglycerides exceed 400 mg/dL (4.5 mmol/L), when the patient is non-fasting, or in patients with type I or III hyperlipoproteinemia. In these cases, direct LDL measurement is recommended.
What is the difference between LDL and VLDL cholesterol?
LDL (low-density lipoprotein) carries cholesterol to tissues and is often called 'bad cholesterol' because high levels promote plaque buildup in arteries. VLDL (very-low-density lipoprotein) carries triglycerides. VLDL is estimated as Triglycerides / 5 in mg/dL or Triglycerides / 2.22 in mmol/L. Together with HDL, they make up total cholesterol.
What is the ideal LDL cholesterol target for heart disease prevention?
For low-risk individuals, LDL below 100 mg/dL (2.6 mmol/L) is considered optimal. For medium-risk individuals (SCORE 5-10%), target is below 100 mg/dL. For high-risk individuals (SCORE >10%), target is below 70 mg/dL (1.8 mmol/L). In the US, ATP III guidelines recommend LDL below 100 mg/dL for optimal cardiovascular health. In the UK, NICE guidelines recommend statin therapy for those with LDL above 3.0 mmol/L (116 mg/dL) and high CVD risk.
How can I lower my LDL cholesterol naturally?
To lower LDL cholesterol naturally: increase soluble fiber intake (oats, barley, beans, apples, psyllium); reduce saturated and trans fats; eat fatty fish rich in omega-3s (salmon, mackerel, sardines); exercise regularly (150+ minutes of moderate activity per week); maintain healthy weight; quit smoking; and limit alcohol consumption. In some cases, medication like statins may be prescribed by a doctor.
Do cholesterol units mg/dL and mmol/L differ?
Yes. The United States, India, and many other countries use mg/dL (milligrams per deciliter). The United Kingdom, Canada, Australia, and most European countries use mmol/L (millimoles per liter). To convert: 1 mmol/L = 38.67 mg/dL, or mg/dL ÷ 38.67 = mmol/L. This calculator supports both units — simply select your preferred unit before entering values.