mg/dL (US Standard)
mmol/L (International Standard)
Estimated LDL: 0mg/dL
Note: The Friedewald formula is less accurate when triglycerides are above 400 mg/dL (4.52 mmol/L).
Understanding Your LDL Cholesterol Result
Low-Density Lipoprotein (LDL) is often referred to as "bad" cholesterol. High levels of LDL lead to the buildup of plaque in your arteries, a condition known as atherosclerosis, which increases the risk of heart disease and stroke.
The Friedewald Formula
This calculator uses the clinically recognized Friedewald Equation to estimate your LDL levels based on other components of a standard lipid panel:
Disclaimer: This calculator is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions regarding a medical condition.
function updateUnits() {
var unit = document.getElementById("ldlUnit").value;
var unitTexts = document.getElementsByClassName("unit-text");
var totalInput = document.getElementById("totalChol");
var hdlInput = document.getElementById("hdlChol");
var triInput = document.getElementById("triglycerides");
var unitLabel = unit === "mgdl" ? "mg/dL" : "mmol/L";
for (var i = 0; i < unitTexts.length; i++) {
unitTexts[i].innerText = unitLabel;
}
if (unit === "mgdl") {
totalInput.placeholder = "e.g. 200";
hdlInput.placeholder = "e.g. 50";
triInput.placeholder = "e.g. 150";
} else {
totalInput.placeholder = "e.g. 5.1";
hdlInput.placeholder = "e.g. 1.3";
triInput.placeholder = "e.g. 1.7";
}
}
function calculateLDL() {
var unit = document.getElementById("ldlUnit").value;
var total = parseFloat(document.getElementById("totalChol").value);
var hdl = parseFloat(document.getElementById("hdlChol").value);
var tri = parseFloat(document.getElementById("triglycerides").value);
var resultDiv = document.getElementById("ldlResult");
var ldlValueSpan = document.getElementById("ldlValue");
var ldlCategoryPara = document.getElementById("ldlCategory");
var warningDiv = document.getElementById("ldlWarning");
if (isNaN(total) || isNaN(hdl) || isNaN(tri) || total <= 0 || hdl <= 0 || tri <= 0) {
alert("Please enter valid positive numbers for all fields.");
return;
}
var ldl = 0;
var triLimit = unit === "mgdl" ? 400 : 4.52;
if (unit === "mgdl") {
ldl = total – hdl – (tri / 5);
} else {
ldl = total – hdl – (tri / 2.2);
}
if (ldl triLimit) {
warningDiv.style.display = "block";
} else {
warningDiv.style.display = "none";
}
// Convert to mg/dL for standardized categorization logic
var ldlMgdl = unit === "mgdl" ? ldl : ldl * 38.67;
var category = "";
var bgColor = "";
var textColor = "";
if (ldlMgdl < 100) {
category = "Optimal";
bgColor = "#d4edda";
textColor = "#155724";
} else if (ldlMgdl < 130) {
category = "Near Optimal / Above Optimal";
bgColor = "#d1ecf1";
textColor = "#0c5460";
} else if (ldlMgdl < 160) {
category = "Borderline High";
bgColor = "#fff3cd";
textColor = "#856404";
} else if (ldlMgdl < 190) {
category = "High";
bgColor = "#ffe5d0";
textColor = "#854100";
} else {
category = "Very High";
bgColor = "#f8d7da";
textColor = "#721c24";
}
ldlCategoryPara.innerText = category;
resultDiv.style.backgroundColor = bgColor;
ldlCategoryPara.style.color = textColor;
resultDiv.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}