Calculate your LDL cholesterol using the Friedewald equation and see your total cholesterol-to-HDL ratio.
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Cholesterol panels typically report total cholesterol, HDL (often called "good" cholesterol), and triglycerides directly from a blood test, while LDL ("bad" cholesterol) is usually calculated rather than measured directly. This calculator uses the Friedewald equation — LDL = Total Cholesterol − HDL − (Triglycerides ÷ 5) — the standard method used by most laboratories, which is reliable when triglycerides are below 400 mg/dL. Cholesterol categories used here follow widely referenced clinical thresholds for total cholesterol and LDL, alongside the total-to-HDL ratio, a useful secondary indicator of cardiovascular risk. The liver produces most of the cholesterol circulating in blood regardless of diet, which is why dietary cholesterol has a weaker effect on blood levels than once believed. Doctors often use the ratio of total cholesterol to HDL, or LDL to HDL, as a more predictive marker of heart disease risk than the total number alone, since high HDL (the "good" kind) can raise the total while actually being a favorable sign.
Cholesterol is a waxy, fat-like substance the body needs for building cell membranes, producing hormones, and making vitamin D, and the liver produces most of what circulates in blood regardless of diet — which is why cholesterol levels don't always track simply with how much cholesterol someone eats. What actually predicts cardiovascular risk is less about the total number and more about the balance between different types of lipoproteins that carry cholesterol through the bloodstream.
LDL (low-density lipoprotein) is often called "bad" cholesterol because elevated levels are strongly associated with plaque buildup in artery walls, a process called atherosclerosis that increases heart attack and stroke risk. HDL (high-density lipoprotein) is called "good" cholesterol because it helps transport excess cholesterol back to the liver for removal, and higher HDL levels are generally protective. Triglycerides, a different type of blood fat entirely, rise with excess calorie intake — particularly from refined carbohydrates and alcohol — and elevated levels are an independent cardiovascular risk factor.
Beyond the individual numbers, ratios like total cholesterol to HDL are used clinically because they capture the balance rather than any single value in isolation — a total cholesterol reading that looks high might carry less risk if HDL is also proportionally high, while a "normal-looking" total reading paired with low HDL and high triglycerides can actually indicate meaningful risk. Guidelines from organizations like the American Heart Association generally recommend a total cholesterol-to-HDL ratio below 5, with lower generally being better, though target ranges vary by individual risk factors including age, family history, blood pressure, and smoking status.
This calculator provides an educational estimate based on standard reference ranges, not a diagnosis — an actual lipid panel from a blood draw, interpreted by a doctor alongside personal and family medical history, is the only reliable way to assess real cardiovascular risk and determine whether lifestyle changes or medication are appropriate.
Below 200 mg/dL is generally considered desirable, 200-239 mg/dL borderline high, and 240 mg/dL or above high.
Not as directly as once thought — the liver adjusts its own production in response to diet for most people, though saturated and trans fats affect blood cholesterol more consistently than dietary cholesterol itself.
A lower ratio is better; a ratio below about 3.5-5 is generally considered desirable, though your doctor may use different thresholds.
The Friedewald equation becomes inaccurate above 400 mg/dL triglycerides, and a direct LDL blood test is recommended instead.