The LDL Cholesterol Calculator estimates low-density lipoprotein (LDL) levels to assess cardiovascular risk. Choose between the Friedewald formula (fasting samples) or Martin/Hopkins method (non-fasting) for accuracy.
Formulas
1. Friedewald Formula (Most Common):
LDL (mg/dL) =
Total Cholesterol −
HDL −
(
Triglycerides
5
)
*Friedewald formula (valid when Triglycerides < 400 mg/dL)
Limitations:
- Requires fasting triglycerides <400 mg/dL.
- Less accurate if triglycerides >200 mg/dL.
2. Martin/Hopkins Method (More Accurate):
LDL =
Total Cholesterol −
HDL −
(
Triglycerides
Adjustable Factor
)
Adjustable Factor:
| Triglycerides (mg/dL) | Factor |
|---|---|
| 75–99 | 3.1 |
| 100–149 | 3.4 |
| 150–199 | 3.8 |
| 200–299 | 4.5 |
| 300–399 | 5.6 |
3. NIH Equation (For mmol/L)
LDL (mmol/L) =
Total Cholesterol −
HDL −
(
Triglycerides
2.2
)
*SI units version: Factor 2.2 used for mmol/L conversion (vs 5 for mg/dL)
🧮 LDL Cholesterol Calculator
⚙️ Select Unit System:
How to Use the Calculator
- Input Values:
- Total Cholesterol (mg/dL or mmol/L).
- HDL (mg/dL or mmol/L).
- Triglycerides (mg/dL or mmol/L).
- Select Formula: Friedewald (default) or Martin/Hopkins.
- Calculate LDL.
Example (Friedewald Formula)
- Total Cholesterol = 200 mg/dL
- HDL = 50 mg/dL
- Triglycerides = 150 mg/dL
LDL (mg/dL) =
Total Cholesterol −
HDL −
(
Triglycerides
5
)
*Friedewald formula (valid when Triglycerides < 400 mg/dL)
LDL (mg/dL) =
200 −
50 −
(
150
5
)
LDL (mg/dL) =
200 −
50 −
(30) −
= 120 (mg/dL)
Normal LDL Ranges
| Category | LDL (mg/dL) | Risk Level |
|---|---|---|
| Optimal | <100 | Low |
| Near Optimal | 100–129 | Moderate |
| Borderline High | 130–159 | High |
| High | 160–189 | Very High |
| Very High | ≥190 | Extreme |
Clinical Significance
| LDL Level | Interpretation |
|---|---|
| <70 | Ideal for high-risk patients (e.g., CVD, diabetes) |
| >160 | Increased atherosclerosis risk; consider statins |
Key Notes
- Triglyceride Limits:
- Friedewald formula invalid if triglycerides ≥400 mg/dL (use direct LDL measurement).
- Non-Fasting Samples:
- Use Martin/Hopkins for non-fasting triglycerides.
- Unit Conversions:
- 1 mmol/L = 38.67 mg/dL (for cholesterol/triglycerides).
Comparison of Methods
| Method | Accuracy | Triglyceride Range | Fasting Required? |
|---|---|---|---|
| Friedewald | Moderate | <400 mg/dL | Yes |
| Martin/Hopkins | High | 75–399 mg/dL | No |
| Direct LDL | Most accurate | Any | No |
