LDL Cholesterol Calculator

If you've recently had blood work done, chances are your lab report includes total cholesterol, HDL, and triglycerides — but not always a clear LDL number. This calculator fills that gap. Enter those three values, and you'll get an instant LDL estimate based on the Friedewald equation, the same formula used in clinical labs worldwide.

LDL cholesterol is the number your doctor pays closest attention to when assessing heart disease risk, and for good reason — it's the type of cholesterol most directly involved in plaque buildup inside your arteries. Whether you're seeing elevated cholesterol for the first time or tracking your progress after starting treatment, understanding your LDL gives you a clearer picture of where you stand.

This calculator works with both mg/dL (standard in the United States) and mmol/L (used in most other countries), so you can enter values exactly as they appear on your lab report.

LDL stands for low-density lipoprotein — one of several particles that carry cholesterol through your bloodstream. Your body actually needs cholesterol to build cell membranes, produce vitamin D, and make hormones. The problem isn't cholesterol itself; it's when too much of it rides around on LDL particles.

When LDL levels are high, excess cholesterol gets deposited into artery walls. Over time, these deposits harden into plaques that narrow your blood vessels and reduce blood flow — a condition called atherosclerosis. If a plaque ruptures, it can trigger a blood clot that blocks an artery entirely, leading to a heart attack or stroke.

That's why LDL is called "bad" cholesterol, while HDL (high-density lipoprotein) gets the "good" label — HDL particles actually pick up excess cholesterol and carry it back to the liver for disposal.

Most routine blood tests don't measure LDL directly. Instead, your lab calculates it from the other values on your lipid panel — total cholesterol, HDL, and triglycerides. That's exactly what this calculator does, using the same Friedewald equation that labs have relied on since 1972.

Heart disease remains the leading cause of death worldwide, and LDL cholesterol is one of the strongest modifiable risk factors. The relationship is direct: the higher your LDL, the greater your risk of cardiovascular events.

To put it in perspective, research published in the Journal of the American College of Cardiology shows that for every 38.7 mg/dL (1 mmol/L) reduction in LDL cholesterol, the risk of major cardiovascular events drops by roughly 22%. That's a significant return for a single number moving in the right direction.

The good news is that unlike some risk factors you can't change — your age, genetics, family history — LDL cholesterol responds well to intervention. Diet, exercise, and when necessary, medication can all bring it down. Knowing your number is the starting point for that conversation with your doctor.

Your LDL doesn't tell the whole story on its own, though. It's one piece of a bigger lipid profile that includes HDL cholesterol, triglycerides, total cholesterol, and sometimes cholesterol ratios. Together, these give your healthcare provider a more complete picture of your cardiovascular risk. But among all those numbers, LDL is typically the primary treatment target.

So what does your calculated LDL actually mean? These are the classification ranges used by the American Heart Association and the National Cholesterol Education Program:

Below 100 mg/dL (2.6 mmol/L) is where most people want to be. If you already have heart disease, diabetes, or multiple cardiovascular risk factors, your doctor may push for an even more aggressive target — below 70 mg/dL (1.8 mmol/L). Some recent guidelines even suggest below 55 mg/dL for very high-risk patients.

100 to 129 mg/dL is generally fine if you don't have other major risk factors. But if you smoke, have high blood pressure, or carry a strong family history of early heart disease, your doctor might still want that number lower.

130 mg/dL and above usually signals it's time for a serious conversation about lifestyle changes. At 160 mg/dL and up, medication often enters the discussion — and above 190 mg/dL, most guidelines recommend treatment regardless of other risk factors.

One thing to keep in mind: these ranges are population-level guidelines. Your personal target depends on your complete risk profile, which is why it's always worth reviewing your results with your healthcare provider rather than drawing conclusions from a chart alone.

This calculator uses the Friedewald equation, published in 1972 by William T. Friedewald and colleagues. Despite being over 50 years old, it's still the most widely used method for estimating LDL cholesterol in clinical practice around the world.

The math is straightforward. Your total cholesterol is essentially made up of three components: LDL, HDL, and VLDL (very low-density lipoprotein). Since standard blood tests don't measure VLDL directly, the Friedewald equation estimates it by dividing triglycerides by 5 (in mg/dL) or by 2.2 (in mmol/L). Then it's simple subtraction:

In mg/dL: LDL = Total Cholesterol − HDL − (Triglycerides ÷ 5)

In mmol/L: LDL = Total Cholesterol − HDL − (Triglycerides ÷ 2.2)

Quick example in mg/dL:

• Total Cholesterol: 220
• HDL: 55
• Triglycerides: 150
• LDL = 220 − 55 − (150 ÷ 5) = 220 − 55 − 30 = 135 mg/dL — borderline high

Quick example in mmol/L:

• Total Cholesterol: 5.7
• HDL: 1.4
• Triglycerides: 1.7
• LDL = 5.7 − 1.4 − (1.7 ÷ 2.2) = 5.7 − 1.4 − 0.77 = 3.53 mmol/L — borderline high

The division by 5 (or 2.2) works because, on average, about one-fifth of your triglyceride value equals the cholesterol carried by VLDL particles. This assumption holds up well for most people — but it starts to break down when triglycerides are very high, which we'll cover in the accuracy section below.

1. Grab your lipid panel results. You need three numbers from your blood test: total cholesterol, HDL cholesterol, and triglycerides. On most lab reports, look for "TC" or "Total Chol," "HDL-C," and "TG" or "Trig."
2. Pick your unit. Select mg/dL if your results are in milligrams per deciliter (standard in the U.S.) or mmol/L for millimoles per liter (standard in Europe, Canada, Australia, and most other countries).
3. Enter your values. Type each number into the matching field. The calculator updates instantly — no need to click a button.
4. Check your result. Your estimated LDL appears at the bottom. Compare it to the classification table above to see where you fall, and bring the number to your next doctor's appointment if you haven't already discussed it.

• Total Cholesterol: 180 mg/dL | HDL: 60 mg/dL | Triglycerides: 100 mg/dL
• LDL = 180 − 60 − 20 = 100 mg/dL (Optimal)

This is what a well-balanced panel looks like. The HDL at 60 mg/dL is strong — anything above 60 is considered protective — and the triglycerides at 100 are well within normal range. The LDL lands right at the optimal cutoff. No immediate action needed beyond maintaining healthy habits.

• Total Cholesterol: 240 mg/dL | HDL: 45 mg/dL | Triglycerides: 175 mg/dL
• LDL = 240 − 45 − 35 = 160 mg/dL (High)

This is the kind of result that can catch people off guard. The total cholesterol seems "a little high," but the real concern is under the surface — a lower HDL combined with elevated triglycerides pushes LDL into the high range. This person would benefit from discussing dietary changes with their doctor, and possibly medication depending on other risk factors.

• Total Cholesterol: 170 mg/dL | HDL: 55 mg/dL | Triglycerides: 120 mg/dL
• LDL = 170 − 55 − 24 = 91 mg/dL (Optimal)

Someone on statins or other lipid-lowering medication might see numbers like this. Comparing to a previous result — say, the borderline example above — shows clear progress. This kind of improvement is exactly why regular retesting matters: it confirms the treatment plan is working and keeps you motivated.

• Total Cholesterol: 210 mg/dL | HDL: 40 mg/dL | Triglycerides: 350 mg/dL
• LDL = 210 − 40 − 70 = 100 mg/dL (Near optimal...but take this with caution)

On paper, this LDL looks fine. But triglycerides at 350 mg/dL are pushing the limits of where the Friedewald equation stays reliable. Above 400 mg/dL, the formula shouldn't be used at all. At this level, the actual LDL could be meaningfully different from the estimate. If your triglycerides are this high, ask your doctor about a direct LDL measurement for a more accurate reading.

• Total Cholesterol: 6.2 mmol/L | HDL: 1.2 mmol/L | Triglycerides: 2.0 mmol/L
• LDL = 6.2 − 1.2 − (2.0 ÷ 2.2) = 6.2 − 1.2 − 0.91 = 4.09 mmol/L (Borderline high)

For readers using mmol/L, this shows a result that falls in the borderline-high range. The HDL at 1.2 mmol/L is on the lower end (ideally above 1.5 mmol/L for women, 1.2 mmol/L for men), and the elevated total cholesterol contributes to a higher LDL.

If you haven't had your cholesterol checked recently, here's a general guide:

• Adults 20 and older should have a lipid panel at least every 4 to 6 years if they're at average risk, according to the American Heart Association.
• Ages 40 to 75 is when cardiovascular risk assessment becomes especially important. Your doctor will likely check cholesterol as part of calculating your 10-year heart disease risk.
• If you have risk factors — high blood pressure, diabetes, obesity, smoking, or a family history of early heart disease — your doctor may want lipid panels annually or even every few months while adjusting treatment.
• Children and teens with a family history of high cholesterol or early heart disease may be tested as young as age 2, though routine screening typically starts between ages 9 and 11.
• After starting medication, your doctor will usually recheck at 4 to 12 weeks to see how you're responding, then every 3 to 12 months going forward.

If you're tracking your cholesterol over time, this calculator is a quick way to estimate your LDL between doctor visits — just make sure you're using results from the same type of test (ideally fasting) to keep your comparisons consistent.

The Friedewald equation gives a solid estimate for most people, but a few things can shift its accuracy:

Fasting vs. non-fasting blood draws. Lipid panels are most reliable after a 9-to-12-hour fast. Food raises triglyceride levels temporarily, and since the equation uses triglycerides to estimate VLDL, a non-fasting sample can make your calculated LDL appear lower than it actually is.

Very high triglycerides. The equation's key assumption — that VLDL cholesterol equals roughly one-fifth of your triglycerides — holds up well for most people. But when triglycerides exceed 400 mg/dL (4.5 mmol/L), that ratio shifts and the formula can significantly underestimate your real LDL. Newer methods like the Martin-Hopkins equation handle this better, but the Friedewald remains the default in most labs. If your triglycerides are above 400 mg/dL, ask your doctor about a direct LDL measurement.

Very low LDL levels. On the other end, if your LDL is below 70 mg/dL — common with high-dose statin therapy — the Friedewald equation can also lose accuracy. This matters when your doctor is trying to confirm you've hit an aggressive treatment target.

Certain health conditions. Liver disease, kidney disease (nephrotic syndrome), and some genetic lipid disorders can alter the normal ratios between lipoproteins, making any calculated estimate less reliable.

Recent illness or surgery. Cholesterol levels often drop temporarily after a heart attack, major surgery, or severe infection. A lipid panel drawn during recovery may not reflect your usual baseline.

If any of these apply to you, mention it when discussing your results with your doctor. A single cholesterol reading is a snapshot — not a verdict.

If your result is higher than you'd like, there's genuine reason for optimism. LDL is one of the most treatable cardiovascular risk factors, and even modest changes can make a real difference.

Cut back on saturated fat. This is the single most impactful dietary change for most people. Saturated fat — found in red meat, butter, cheese, and fried foods — directly raises LDL levels. Swapping in unsaturated fats from olive oil, avocados, nuts, and fatty fish like salmon can lower LDL by 10 to 15%. You don't have to overhaul everything at once — even replacing one or two sources of saturated fat per day adds up.

Add more soluble fiber. Soluble fiber binds to cholesterol in your digestive tract and helps your body remove it. Oats, barley, beans, lentils, apples, and citrus fruits are all good sources. Research suggests that 5 to 10 grams of soluble fiber daily can lower LDL by about 5 to 10% — and a bowl of oatmeal gets you roughly 2 grams of that.

Move more consistently. Regular aerobic exercise — brisk walking, cycling, swimming — for at least 150 minutes per week improves your lipid profile broadly. It's especially effective at raising HDL, which helps counterbalance LDL. Even short daily walks are better than nothing, and the benefits accumulate over time.

Lose weight if you need to. Excess weight, particularly around the midsection, is closely tied to higher LDL and triglycerides. Losing just 5 to 10% of your body weight (that's 10 to 20 pounds for a 200-pound person) can produce measurable improvements in your next lipid panel.

Quit smoking. Smoking doesn't directly raise LDL, but it lowers HDL and damages artery walls — making the LDL you do have more dangerous. Within a few weeks of quitting, HDL begins to recover. Within a year, your excess heart disease risk drops by half.

Medication is a tool, not a failure. If lifestyle changes aren't enough — or if your risk level calls for faster intervention — statins and other lipid-lowering drugs can reduce LDL by 30 to 50% or more. For people with established heart disease or very high LDL, medication isn't optional; it's one of the most evidence-backed interventions in all of cardiology. Your doctor can help you weigh the benefits against any concerns.

This calculator uses the Friedewald equation (LDL = Total Cholesterol − HDL − Triglycerides/5) to estimate LDL cholesterol. Results are intended for informational purposes and should not replace professional medical advice. Always review your cholesterol numbers with your healthcare provider, who can interpret them alongside your full health history, risk factors, and treatment goals. The Friedewald equation is unreliable when triglycerides exceed 400 mg/dL (4.5 mmol/L) — in those cases, ask your doctor about a direct LDL measurement.