LDL Cholesterol Calculator

Use the Friedewald equation to estimate your LDL ("bad") cholesterol from a standard lipid panel. This tool is for adults, supports mg/dL and mmol/L units, and runs completely offline.

Educational only, not medical advice.

Lipid Panel

mg/dL mmol/L

Total Cholesterol

Typical range: 125–200 mg/dL

HDL Cholesterol

Typical range: 40–60 mg/dL

Triglycerides

For Friedewald: <400 mg/dL

Estimated LDL Cholesterol

Enter values and click Calculate

Interpretation (General Adult Guidance)

LDL Range	Category	Typical Clinical Note
<100 mg/dL (<2.6 mmol/L)	Optimal	Ideal for heart health, especially with high risk.
100–129 mg/dL (2.6–3.3 mmol/L)	Near Optimal	Acceptable for low-risk individuals.
130–159 mg/dL (3.4–4.1 mmol/L)	Borderline High	Lifestyle changes often recommended.
160–189 mg/dL (4.1–4.9 mmol/L)	High	Discuss with clinician; may need intervention.
≥190 mg/dL (≥4.9 mmol/L)	Very High	Strongly consider medical evaluation.

Note: Individual targets vary based on risk factors (age, diabetes, prior heart events). This table is for general education.

Understanding the Friedewald Estimate

The Friedewald equation is a widely used formula to estimate LDL cholesterol without a direct lab measurement. It's calculated from a standard lipid panel (Total Cholesterol, HDL, and Triglycerides).

Why it matters: Direct LDL tests can be more expensive. This estimate helps in routine screening and tracking trends. However, it becomes less accurate with very high triglycerides (>400 mg/dL) or in certain conditions (e.g., diabetes, very low LDL).

Step-by-step guide for this tool:

Enter your latest lipid panel results. Use either mg/dL or mmol/L (toggle the switch).
Ensure your triglyceride value is under 400 mg/dL (4.52 mmol/L) for a valid estimate.
Click "Calculate LDL". The tool will show your estimated LDL, the calculation steps, and a general interpretation.

Realistic examples:

Example 1: Total 200 mg/dL, HDL 50 mg/dL, Triglycerides 150 mg/dL → LDL = 200 - 50 - (150/5) = 120 mg/dL (Near Optimal).
Example 2 (mmol/L): Total 5.2 mmol/L, HDL 1.3 mmol/L, Triglycerides 1.7 mmol/L → LDL = 5.2 - 1.3 - (1.7/2.2) ≈ 3.2 mmol/L (Borderline High).

Quick Lipid Unit Converter

Convert individual lipid values between mg/dL and mmol/L for reference.

Value

Convert

100 mg/dL ≈ 2.59 mmol/L

Conversion factor: 1 mmol/L = 38.67 mg/dL for cholesterol; 1 mmol/L = 88.57 mg/dL for triglycerides.

Frequently Asked Questions

When is the Friedewald equation inaccurate?

It becomes unreliable when triglycerides exceed 400 mg/dL (4.52 mmol/L), in non-fasting samples, or with very low LDL levels (<70 mg/dL). In these cases, a direct LDL measurement is needed.

Why does my calculated LDL differ from my lab report?

Labs may use different methods (direct measurement, alternative equations like Martin-Hopkins). The Friedewald equation is an estimate. Small variations are normal; large discrepancies should be discussed with your clinician.

How can I measure my lipids accurately at home?

For reliable results, a fasting blood test (9-12 hours no food, water only) is standard. Home test kits vary in accuracy; follow instructions carefully and consider confirming with a lab test.

When should I seek professional help?

If your LDL is consistently high (≥160 mg/dL or 4.1 mmol/L), or you have other risk factors (family history, diabetes, high blood pressure, smoking), schedule a visit. Seek immediate care for chest pain, shortness of breath, or symptoms of a heart attack.

Formulas & Assumptions

Friedewald Equation (mg/dL): LDL = Total Cholesterol – HDL – (Triglycerides / 5)
Friedewald Equation (mmol/L): LDL = Total Cholesterol – HDL – (Triglycerides / 2.2)
Assumes triglycerides are <400 mg/dL (4.52 mmol/L) and VLDL cholesterol ≈ Triglycerides / 5 (or /2.2).
Unit Conversions: 1 mmol/L cholesterol = 38.67 mg/dL; 1 mmol/L triglycerides = 88.57 mg/dL.
All inputs are rounded to 2 decimal places internally; results are displayed to 1 decimal place.
Interpretation bands based on general public health guidance (ACC/AHA).

For informational and educational purposes only. Estimates depend on your inputs and simplifying assumptions. This tool is not medical advice and does not diagnose or treat any condition. If you have symptoms, abnormal readings, or urgent concerns, contact a qualified healthcare professional.

Sources & References: Common unit conversions and measurement best practices; Typical wellness metric ranges and public health guidance concepts; General nutrition and hydration guidance concepts.

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