LDL Calculator
Free LDL Calculator with medically-sourced formulas. Enter your measurements for personalized, accurate health insights.
Reviewed for accuracy by Rahul Singh, Health & Wellness Specialist
Medical disclaimer: This calculator is provided for educational and informational purposes only and does not constitute medical advice, diagnosis, or treatment. Results are general estimates and may not reflect your individual circumstances. Always consult a qualified healthcare professional before making decisions about your health.
LDL Calculator
Calculator
Adjust values & calculateEnter your values below. Every result is computed in your browser — no data is sent to any server.
Formula: LDL = Total Cholesterol - HDL - (Triglycerides / 5)
Worked example — LDL = 135 mg/dL (Borderline High) | Non-HDL = 165 mg/dL | TC/HDL Ratio = 4.0 (Average Risk)
Formula
LDL = Total Cholesterol - HDL - (Triglycerides / 5)
The Friedewald equation estimates LDL cholesterol by subtracting HDL and estimated VLDL (triglycerides divided by 5) from total cholesterol. All values are in mg/dL. This formula is valid when triglycerides are below 400 mg/dL.
Worked Examples
Example 1: Standard Lipid Panel LDL Calculation
Problem:A patient has Total Cholesterol of 220 mg/dL, HDL of 55 mg/dL, and Triglycerides of 150 mg/dL. Calculate the estimated LDL cholesterol.
Solution:Using Friedewald equation: LDL = TC - HDL - (TG / 5) LDL = 220 - 55 - (150 / 5) LDL = 220 - 55 - 30 LDL = 135 mg/dL VLDL = 150 / 5 = 30 mg/dL Non-HDL = 220 - 55 = 165 mg/dL TC/HDL Ratio = 220 / 55 = 4.0
Result:LDL = 135 mg/dL (Borderline High) | Non-HDL = 165 mg/dL | TC/HDL Ratio = 4.0 (Average Risk)
Example 2: High Risk Patient LDL Assessment
Problem:A diabetic patient has Total Cholesterol of 250 mg/dL, HDL of 38 mg/dL, and Triglycerides of 300 mg/dL. Calculate LDL and assess risk.
Solution:Using Friedewald equation: LDL = TC - HDL - (TG / 5) LDL = 250 - 38 - (300 / 5) LDL = 250 - 38 - 60 LDL = 152 mg/dL Using Iranian formula: LDL = 250/1.19 + 300/1.9 - 38/1.1 - 38 LDL = 210.1 + 157.9 - 34.5 - 38 = 295.5 (Note: discrepancy suggests direct LDL testing needed) TC/HDL Ratio = 250 / 38 = 6.58 (High Risk)
Result:LDL = 152 mg/dL (Borderline High) | TC/HDL Ratio = 6.58 (High Risk) | Target for diabetics: < 70 mg/dL
Frequently Asked Questions
What is LDL cholesterol and why is it important?
LDL (Low-Density Lipoprotein) cholesterol is often called bad cholesterol because it carries cholesterol particles throughout your body and can build up in the walls of your arteries. This buildup, known as atherosclerosis, narrows the arteries and increases the risk of heart attack and stroke. High LDL levels are one of the most significant modifiable risk factors for cardiovascular disease. The American Heart Association recommends keeping LDL below 100 mg/dL for most adults, and below 70 mg/dL for those at very high cardiovascular risk. Regular monitoring through blood tests helps track your levels over time.
How does the Friedewald equation calculate LDL cholesterol?
The Friedewald equation is the most widely used method to estimate LDL cholesterol from a standard lipid panel. The formula is LDL = Total Cholesterol minus HDL minus (Triglycerides divided by 5), where all values are in mg/dL. This equation works by subtracting the known cholesterol fractions (HDL and VLDL) from total cholesterol, with VLDL estimated as one-fifth of triglycerides. The formula is accurate when triglycerides are below 400 mg/dL, but becomes unreliable at higher triglyceride levels. In those cases, a direct LDL measurement through laboratory testing is recommended instead.
What is the difference between Friedewald and Iranian formula for LDL?
The Iranian formula (also known as the Anandaraja equation) was developed as an alternative to the Friedewald equation and uses a different mathematical approach: LDL = TC/1.19 + TG/1.9 - HDL/1.1 - 38. Some studies suggest the Iranian formula may be more accurate when triglyceride levels are between 200 and 400 mg/dL, where the Friedewald equation can underestimate LDL. However, the Friedewald equation remains the clinical standard worldwide. Comparing results from both formulas can give you a range of your estimated LDL, which is especially useful when triglycerides are moderately elevated.
What are optimal LDL cholesterol levels for heart health?
According to the American Heart Association and National Lipid Association guidelines, LDL cholesterol levels are classified as follows: below 100 mg/dL is optimal, 100 to 129 mg/dL is near optimal, 130 to 159 mg/dL is borderline high, 160 to 189 mg/dL is high, and 190 mg/dL or above is very high. For individuals who have already had a cardiovascular event or have diabetes, the target LDL is typically below 70 mg/dL. Lifestyle changes including diet, exercise, and weight management can lower LDL by 10 to 20 percent, while statin medications can reduce LDL by 30 to 50 percent or more.
Why are triglycerides important in LDL calculation?
Triglycerides play a crucial role in LDL estimation because the Friedewald equation uses triglyceride levels to estimate VLDL cholesterol, which is then subtracted from total cholesterol. The assumption is that VLDL equals triglycerides divided by 5, which holds true for most people with normal to moderately elevated triglycerides. When triglycerides exceed 400 mg/dL, this ratio breaks down and the calculated LDL becomes inaccurate. High triglycerides independently increase cardiovascular risk and are often associated with metabolic syndrome, obesity, and insulin resistance. Fasting for 9 to 12 hours before testing ensures the most accurate triglyceride measurement.
What is the TC/HDL cholesterol ratio and what does it indicate?
The total cholesterol to HDL ratio is calculated by dividing your total cholesterol by your HDL cholesterol level. This ratio is considered a strong predictor of cardiovascular risk by many cardiologists. A ratio below 3.5 indicates low cardiovascular risk, between 3.5 and 5.0 represents average risk, and above 5.0 suggests elevated cardiovascular risk. For example, a total cholesterol of 200 with HDL of 60 gives a ratio of 3.3, which is favorable. The ratio captures the balance between protective HDL and potentially harmful cholesterol, making it sometimes more informative than looking at individual numbers alone.
How can I lower my LDL cholesterol naturally?
Several evidence-based strategies can lower LDL cholesterol without medication. A heart-healthy diet rich in soluble fiber from oats, beans, and fruits can reduce LDL by 5 to 10 percent. Replacing saturated fats with unsaturated fats from olive oil, nuts, and avocados further reduces LDL. Regular aerobic exercise of 150 minutes per week can lower LDL by 5 to 10 percent and raise protective HDL. Losing 5 to 10 percent of body weight if overweight has significant benefits for all lipid levels. Plant sterols and stanols found in fortified foods can reduce LDL by an additional 6 to 15 percent when consumed at 2 grams daily.
What is non-HDL cholesterol and why does it matter?
Non-HDL cholesterol is calculated simply as total cholesterol minus HDL cholesterol, and it includes all the potentially atherogenic (artery-clogging) lipoproteins: LDL, VLDL, IDL, and lipoprotein(a). Many cardiovascular experts consider non-HDL cholesterol a better predictor of heart disease risk than LDL alone because it captures a broader range of harmful particles. The target for non-HDL cholesterol is typically 30 mg/dL higher than your LDL target, so for most adults the goal is below 130 mg/dL. Non-HDL cholesterol has the advantage of being accurate even when triglycerides are elevated, unlike the Friedewald LDL calculation.
Should I fast before getting my cholesterol tested?
Traditional guidelines recommended fasting for 9 to 12 hours before a lipid panel to ensure accurate triglyceride and LDL measurements. However, recent research and updated guidelines from the European Atherosclerosis Society and the American College of Cardiology suggest that non-fasting lipid panels are acceptable for routine screening. Non-fasting total cholesterol and HDL values are very similar to fasting values, while triglycerides may be slightly higher after eating. The Friedewald LDL calculation is most accurate with fasting triglyceride values. If your non-fasting triglycerides exceed 400 mg/dL, your doctor will likely request a follow-up fasting test for more precise results.
How often should I check my cholesterol levels?
The American Heart Association recommends that adults aged 20 and older have their cholesterol checked every 4 to 6 years if they are at low cardiovascular risk. However, more frequent testing every 1 to 2 years is recommended for individuals with risk factors such as family history of heart disease, diabetes, high blood pressure, smoking, or obesity. People already taking cholesterol-lowering medications should have their levels checked 4 to 12 weeks after starting or changing therapy, and then every 3 to 12 months thereafter. Children and adolescents should be screened at least once between ages 9 and 11 and again between ages 17 and 21.
References
Reviewed for accuracy by Rahul Singh, Health & Wellness Specialist · Editorial policy
Related Calculators
🧮Addiction Calculator
Calculate addiction with inputs, formulas, and instant results.
🧮Alcohol Unit Calculator
Calculate alcohol unit with inputs, formulas, and instant results.
🧮AUDIT-C Calculator
Calculate audit ccalculator with inputs, formulas, and instant results.
🧮AUDIT Full Questionnaire Calculator
Calculate auditfull questionnaire with inputs, formulas, and instant results.
🧮AUDIT Score Calculator
Calculate audit score with inputs, formulas, and instant results.
🧮CAGE Questionnaire Calculator
Calculate cagequestionnaire with inputs, formulas, and instant results.
🧮Cigarette Calculator
Calculate cigarette with inputs, formulas, and instant results.
🧮DAST-10 Drug Abuse Screening Calculator
Calculate dast10drug abuse with inputs, formulas, and instant results.