LDL Cholesterol Calculator

This LDL cholesterol calculator estimates your low-density lipoprotein level using the Friedewald equation — the same formula used in clinical practice worldwide. Enter your total cholesterol, HDL cholesterol, and triglycerides from a standard lipid panel, and you'll get your LDL result in seconds, in either mg/dL or mmol/L.

Whether you've just received blood test results and want to double-check the math, or you're actively managing your cholesterol levels and tracking progress over time, this tool gives you an instant, accurate estimate without needing to wait for a lab report interpretation. Understanding your LDL number is one of the most practical steps you can take for your long-term heart health.

LDL stands for low-density lipoprotein — often called "bad" cholesterol, though that label is a bit of an oversimplification. LDL particles carry cholesterol from the liver to cells throughout the body, which is actually a necessary process. The problem arises when LDL levels run too high: excess LDL can deposit cholesterol in the walls of arteries, contributing to plaque buildup and raising the risk of heart attack and stroke over time.

Your total cholesterol reading alone doesn't tell the full story. A high total cholesterol can still reflect a healthy profile if most of it is HDL (high-density lipoprotein, the "good" kind). That's why LDL is tracked separately — it's a much more specific signal of cardiovascular risk.

Unlike HDL and total cholesterol, LDL isn't usually measured directly in a standard blood test. Instead, it's calculated from the other values in your lipid panel using the Friedewald equation, which is exactly what this calculator does.

Cardiovascular disease remains the leading cause of death worldwide, and elevated LDL cholesterol is one of the most well-established and modifiable risk factors. Research consistently shows that lowering LDL reduces the risk of heart attacks, strokes, and other major cardiovascular events — and the relationship is fairly linear: lower LDL means lower risk.

The good news is that LDL is genuinely something you can influence. Diet, exercise, weight, and medication all have real, measurable effects on your LDL level. That makes tracking it meaningful — not as a source of anxiety, but as a tool for understanding what's working and what might need adjusting.

The 2025 guidelines from both the National Lipid Association and the updated ESC/EAS framework reinforce a "lower for longer" approach: achieving a target LDL early and maintaining it consistently over time provides the most cardiovascular benefit.

Once you calculate your LDL, here's how to interpret what you're seeing. Note that optimal targets vary based on your overall cardiovascular risk — the ranges below reflect general population guidelines from the American Heart Association and AHA/ACC framework.

Risk-based targets (2025 guidelines):

If you have specific cardiovascular risk factors, your doctor may aim for a lower LDL target than the general "under 100" recommendation:

• Low cardiovascular risk: LDL below 115 mg/dL (3.0 mmol/L)
• Moderate risk: LDL below 100 mg/dL (2.6 mmol/L)
• High risk (e.g., diabetes, chronic kidney disease): LDL below 70 mg/dL (1.8 mmol/L)
• Very high risk (e.g., known heart disease, prior heart attack): LDL below 55 mg/dL (1.4 mmol/L)

These targets reflect where the evidence points — not where most people start. If your number is higher than the target range for your risk level, that's useful information, not a diagnosis. Always discuss results with your healthcare provider before drawing conclusions or making changes.

The Friedewald equation was developed in 1972 by William Friedewald, Robert Levy, and Donald Fredrickson as a practical way to estimate LDL without a direct measurement. It works because three types of lipoproteins carry almost all the cholesterol in your blood: LDL, HDL, and VLDL (very low-density lipoprotein). If you know total cholesterol, HDL, and can estimate VLDL, you can back-calculate LDL.

VLDL is estimated from triglycerides. In mg/dL, the ratio of triglycerides to VLDL cholesterol is approximately 5:1, giving the formula:

In mg/dL:

LDL = Total Cholesterol − HDL − (Triglycerides ÷ 5)

In mmol/L:

LDL = Total Cholesterol − HDL − (Triglycerides ÷ 2.2)

Worked example (mg/dL):

• Total Cholesterol: 210 mg/dL
• HDL: 55 mg/dL
• Triglycerides: 120 mg/dL
• VLDL estimate: 120 ÷ 5 = 24 mg/dL
• LDL = 210 − 55 − 24 = 131 mg/dL (Borderline High)

Worked example (mmol/L):

• Total Cholesterol: 5.4 mmol/L
• HDL: 1.4 mmol/L
• Triglycerides: 1.3 mmol/L
• VLDL estimate: 1.3 ÷ 2.2 = 0.59 mmol/L
• LDL = 5.4 − 1.4 − 0.59 = 3.41 mmol/L (Borderline High)

The equation is widely validated and used in clinical practice worldwide. It's considered sufficiently accurate for routine cardiovascular risk assessment in most patients.

Using this LDL calculator takes about 30 seconds once you have your lipid panel results in hand.

1. Enter your Total Cholesterol — this is the first value on most lipid panel reports. Select your unit (mg/dL or mmol/L) from the dropdown on the right.
2. Enter your HDL Cholesterol — also labeled "HDL-C" or "High-density lipoprotein" on lab reports. Select the matching unit.
3. Enter your Triglycerides — listed as "TG" or "Triglycerides" on your results. Select the unit.
4. Select your preferred output unit — choose whether you want your LDL result displayed in mg/dL or mmol/L.
5. Read your result — your estimated LDL appears instantly below the inputs. Cross-reference it with the ranges table above to understand what it means.

You don't need to do anything else — there's no submit button. The calculator updates automatically as you enter values.

These examples show how the calculator works across different real-world scenarios.

Example 1 — Healthy Profile

Total Cholesterol: 185, HDL: 62, Triglycerides: 90 (all mg/dL)

LDL = 185 − 62 − (90 ÷ 5) = 105 mg/dL — Near Optimal

This is a solid result. HDL is strong, triglycerides are low, and LDL is just slightly above optimal.

Example 2 — Borderline Concern

Total Cholesterol: 230, HDL: 45, Triglycerides: 170 (all mg/dL)

LDL = 230 − 45 − (170 ÷ 5) = 151 mg/dL — Borderline High

This is worth a conversation with your doctor, particularly if there are other cardiovascular risk factors present.

Example 3 — Tracking Medication Progress

Before statin: TC: 260, HDL: 48, TG: 140 → LDL = 184 mg/dL (High)

After 3 months: TC: 195, HDL: 51, TG: 125 → LDL = 119 mg/dL (Near Optimal)

A reduction of 65 mg/dL — meaningful progress that reflects a 35% drop in LDL.

Example 4 — International Units (mmol/L)

Total Cholesterol: 6.2 mmol/L, HDL: 1.3 mmol/L, Triglycerides: 1.8 mmol/L

LDL = 6.2 − 1.3 − (1.8 ÷ 2.2) = 4.08 mmol/L — High

This is above the borderline threshold and warrants follow-up.

Example 5 — When the Formula Hits Its Limits

Total Cholesterol: 280, HDL: 40, Triglycerides: 450 (all mg/dL)

The Friedewald equation is not reliable when triglycerides exceed 400 mg/dL. In this case, the result would underestimate true LDL. A direct LDL measurement would be needed.

Most adults should have a full lipid panel at least once every 4–6 years as part of routine health screening. However, more frequent testing is recommended if:

• You have a family history of high cholesterol or early heart disease
• You have diabetes, high blood pressure, or chronic kidney disease
• You're overweight or obese
• You smoke or have smoked
• You're a man over 45 or a woman over 55
• You're on cholesterol-lowering medication and monitoring your response

Your doctor may also run a lipid panel at any routine check-up, particularly if there have been changes in your diet, weight, or activity level since your last test. The more consistent you are about tracking it over time, the clearer the picture becomes.

The Friedewald equation is accurate for most people in most situations, but there are a few circumstances where its estimates become less reliable.

Fasting status matters. The formula works best on fasting blood samples — ideally taken after 9–12 hours without food. Non-fasting samples contain higher triglyceride levels from recently eaten food, which throws off the VLDL estimate and causes the formula to underestimate LDL. If you aren't sure whether your test was fasting, check your lab paperwork or ask your doctor.

Very high triglycerides invalidate the result. When triglycerides exceed 400 mg/dL (4.5 mmol/L), the constant ratio used to estimate VLDL breaks down. The calculator result should not be used clinically in this range — a direct LDL test is needed instead.

Certain conditions affect accuracy. People with Type III hyperlipoproteinemia (a genetic lipid disorder) or Type I conditions have abnormal VLDL composition that makes the Friedewald estimate unreliable, regardless of triglyceride levels.

Recently ill or under stress? Acute illness, surgery, and significant stress can temporarily alter cholesterol levels. It's generally best to test when you're stable and healthy for an accurate baseline reading.

If your result is higher than you'd like, the encouraging reality is that LDL responds well to a combination of lifestyle changes — and the impact can be significant. Small, consistent changes often produce meaningful reductions within a few months.

Diet changes with the most evidence:

• Reduce saturated fat (found in red meat, full-fat dairy, coconut oil) — replacing it with unsaturated fats from olive oil, avocados, and nuts can lower LDL by 5–15%
• Increase soluble fiber (oats, beans, lentils, fruit) — 5–10g per day can reduce LDL by an additional 3–5%
• Limit trans fats entirely — these raise LDL and lower HDL simultaneously
• Consider plant sterols/stanols, found in fortified foods — 2g/day has been shown to reduce LDL by 7–10%

Physical activity: Regular aerobic exercise (150 minutes per week of moderate intensity) modestly lowers LDL and significantly raises HDL. Even walking consistently makes a difference.

Weight: Losing 5–10% of body weight if overweight has a meaningful effect on LDL and triglycerides.

Smoking cessation: Quitting smoking raises HDL and improves the overall cholesterol profile.

Medication: Statins are the most commonly prescribed treatment and can reduce LDL by 30–50% or more. Other options include ezetimibe, PCSK9 inhibitors, and bile acid sequestrants. If lifestyle changes alone aren't reaching your target, medication is worth discussing with your doctor.

This calculator is designed for informational use and educational purposes. It estimates LDL cholesterol using the Friedewald equation based on values you provide. Results are not a substitute for medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider to interpret your cholesterol levels in the context of your full health history.