ldl-c calculator

What this LDL-C calculator does

This tool estimates your low-density lipoprotein cholesterol (LDL-C), often called “bad cholesterol,” from three standard lipid panel values: total cholesterol, HDL-C, and triglycerides. LDL-C is one of the most commonly used numbers when discussing cardiovascular risk and treatment goals.

In most routine lab reports, LDL-C is calculated rather than directly measured. That’s exactly what this calculator does: it uses your inputs and returns an estimate in either mg/dL or mmol/L.

The formula used (Friedewald equation)

For mg/dL

LDL-C = Total Cholesterol − HDL-C − (Triglycerides / 5)

For mmol/L

LDL-C = Total Cholesterol − HDL-C − (Triglycerides / 2.2)

The equation assumes a typical relationship between triglycerides and very-low-density lipoprotein cholesterol (VLDL-C). It is simple and widely used, but like all estimates, it has limits.

How to interpret your LDL-C result

General LDL-C categories (commonly referenced in mg/dL) are shown below:

LDL-C Category	mg/dL	mmol/L (approx.)
Optimal	< 100	< 2.59
Near optimal / above optimal	100–129	2.59–3.34
Borderline high	130–159	3.36–4.11
High	160–189	4.14–4.89
Very high	≥ 190	≥ 4.91

Category cutoffs may vary by guideline and individual risk profile. Your clinician may set a more aggressive LDL-C target based on conditions like diabetes, known cardiovascular disease, kidney disease, or family history.

Important limitations

• The Friedewald estimate becomes less reliable when triglycerides are high.
• Many labs caution against using this formula when triglycerides are ≥ 400 mg/dL (or ≥ 4.5 mmol/L).
• Very low LDL-C values or non-fasting samples can also affect accuracy.
• If numbers seem unusual, a repeat panel or direct LDL-C measurement may be recommended.

Why LDL-C matters

LDL particles can contribute to plaque buildup in arteries over time. Lowering LDL-C, especially in people at moderate or high cardiovascular risk, is associated with lower rates of heart attack and stroke. Lifestyle choices and medications can both play a role.

Common LDL-lowering strategies

• Prioritize dietary patterns rich in vegetables, legumes, whole grains, and unsaturated fats.
• Reduce trans fats and limit excess saturated fat intake.
• Increase physical activity (as approved by your clinician).
• Maintain a healthy body weight.
• Discuss medication options (such as statins) when indicated.

Practical tips for using lipid numbers

• Track trends over time, not just one result.
• Review your LDL-C together with non-HDL cholesterol and triglycerides.
• Pair lab results with blood pressure, blood sugar, smoking status, and family history.
• Ask about your personal risk category and treatment goals.

Bottom line

This LDL-C calculator is a quick way to estimate LDL from standard lipid panel values. It’s useful for education and tracking, but it does not replace professional medical evaluation. If your result is high, unexpectedly low, or inconsistent with prior tests, follow up with your healthcare provider.