Use this calculator to estimate your LDL cholesterol level based on your total cholesterol, HDL cholesterol, and triglyceride levels.
Your estimated LDL Cholesterol will appear here.
Understanding LDL Cholesterol Calculation
LDL (Low-Density Lipoprotein) cholesterol, often referred to as "bad" cholesterol, plays a crucial role in cardiovascular health. High levels of LDL cholesterol can contribute to the buildup of plaque in arteries, increasing the risk of heart disease and stroke. While direct measurement of LDL is ideal, it's not always performed, especially if triglyceride levels are within a certain range. In such cases, LDL cholesterol can be estimated using a formula.
The Friedewald Equation
The most commonly used method to estimate LDL cholesterol is the Friedewald Equation. This equation is a simple calculation based on three key lipid values from a standard lipid panel:
Total Cholesterol (TC): The sum of all types of cholesterol in your blood, including LDL, HDL, and VLDL.
HDL Cholesterol (HDL-C): High-Density Lipoprotein cholesterol, often called "good" cholesterol, which helps remove LDL from arteries.
Triglycerides (TG): A type of fat found in your blood.
This formula works best when triglyceride levels are below 400 mg/dL (4.5 mmol/L). If triglyceride levels are significantly higher than this, the Friedewald equation becomes less accurate, and a direct LDL measurement (like ultracentrifugation or homogeneous assay) is recommended by healthcare professionals.
Why is this Calculation Important?
Understanding your LDL cholesterol level is vital for assessing your risk of cardiovascular disease.
Risk Assessment: High LDL is a primary modifiable risk factor for atherosclerosis.
Treatment Guidance: The estimated LDL value helps healthcare providers determine if lifestyle changes or medication are needed to lower cholesterol.
Monitoring Progress: For individuals on cholesterol-lowering therapy, monitoring estimated LDL levels can indicate the effectiveness of treatment.
Interpreting Your Results
General guidelines for LDL cholesterol levels (target values can vary based on individual risk factors and medical history):
Optimal: Less than 100 mg/dL
Near Optimal/Above Optimal: 100-129 mg/dL
Borderline High: 130-159 mg/dL
High: 160-189 mg/dL
Very High: 190 mg/dL and above
Note: This calculator provides an estimate. Always consult with your healthcare provider for a proper diagnosis and personalized medical advice based on your complete health profile.
function calculateLdl() {
var totalCholesterol = parseFloat(document.getElementById("totalCholesterol").value);
var hdlCholesterol = parseFloat(document.getElementById("hdlCholesterol").value);
var triglycerides = parseFloat(document.getElementById("triglycerides").value);
var resultDiv = document.getElementById("result");
// Clear previous results
resultDiv.innerHTML = 'Your estimated LDL Cholesterol will appear here.';
resultDiv.style.color = "#004a99";
// Validate inputs
if (isNaN(totalCholesterol) || isNaN(hdlCholesterol) || isNaN(triglycerides)) {
resultDiv.innerHTML = 'Please enter valid numbers for all fields.';
return;
}
if (triglycerides >= 400) {
resultDiv.innerHTML = 'Triglycerides are too high (>= 400 mg/dL) for accurate Friedewald calculation. Direct LDL measurement is recommended.';
resultDiv.style.color = "#dc3545";
return;
}
if (totalCholesterol < hdlCholesterol) {
resultDiv.innerHTML = 'Total Cholesterol cannot be less than HDL Cholesterol.';
resultDiv.style.color = "#dc3545";
return;
}
// Friedewald Equation calculation
var estimatedLdl = totalCholesterol – hdlCholesterol – (triglycerides / 5);
// Ensure LDL is not negative (can happen with very low TG/HDL)
if (estimatedLdl < 0) {
estimatedLdl = 0;
}
resultDiv.innerHTML = 'Estimated LDL Cholesterol: ' + estimatedLdl.toFixed(2) + ' mg/dL';
resultDiv.style.color = "#28a745"; // Success Green for valid calculation
}