LDL Cholesterol Calculator
Calculate LDL cholesterol (LDL-C) using the Friedewald equation. Supports mg/dL and mmol/L with instant results and LDL-C category interpretation.
LDL Cholesterol Calculator
This calculator estimates LDL-C using the traditional Friedewald equation. The result is an estimated value rather than a direct LDL-C measurement. Accuracy can decrease with elevated triglycerides and in certain low LDL-C ranges.
LDL-C Result
Learn More About LDL Cholesterol
Read the complete LabProSuite guide covering the Friedewald formula, LDL-C calculation, LDL categories, limitations, and clinical interpretation.
Read the Complete LDL Cholesterol Guide →What Is LDL Cholesterol?
Low-density lipoprotein cholesterol (LDL-C) is an important laboratory marker used in cardiovascular risk assessment. LDL particles transport cholesterol through the bloodstream, and elevated LDL-C is associated with atherosclerotic cardiovascular disease risk.
LDL-C can be directly measured by a laboratory assay or estimated from total cholesterol, HDL-C, and triglycerides using a calculation such as the Friedewald equation.
Friedewald LDL Cholesterol Formula
Where:
- TC = Total Cholesterol
- HDL-C = HDL Cholesterol
- TG = Triglycerides
- LDL-C = Estimated LDL Cholesterol
How Does the Friedewald Equation Work?
The traditional Friedewald equation estimates VLDL cholesterol from triglycerides. In mg/dL, estimated VLDL-C is approximately TG divided by 5.
The estimated VLDL-C is then subtracted together with HDL-C from total cholesterol to obtain calculated LDL-C.
LDL Calculation Example
Consider the following hypothetical lipid profile:
- Total Cholesterol = 200 mg/dL
- HDL Cholesterol = 50 mg/dL
- Triglycerides = 150 mg/dL
LDL-C = 200 − 50 − 30
LDL-C = 120 mg/dL
LDL Cholesterol Categories
| LDL-C | Common Description |
|---|---|
| <100 mg/dL | Optimal |
| 100–129 mg/dL | Near Optimal |
| 130–159 mg/dL | Borderline High |
| 160–189 mg/dL | High |
| ≥190 mg/dL | Very High |
These descriptive categories should not be interpreted as individual treatment targets. LDL-C goals depend on overall cardiovascular risk, clinical history, and applicable guidelines.
When Is the Friedewald Equation Not Recommended?
The traditional Friedewald equation is not recommended when triglycerides are 400 mg/dL or higher (approximately 4.52 mmol/L).
Calculated LDL-C can also become less reliable with elevated triglycerides and at very low LDL-C concentrations.
Depending on the clinical and laboratory situation, alternative LDL-C estimation equations or direct LDL-C measurement may be considered.
LDL-C and Non-HDL Cholesterol
Non-HDL cholesterol is another useful lipid parameter and is calculated as:
Non-HDL-C represents cholesterol contained in multiple atherogenic lipoproteins and can provide additional information when evaluating the lipid profile.
How to Use This LDL Calculator
- Enter Total Cholesterol.
- Enter HDL Cholesterol.
- Enter Triglycerides.
- Select mg/dL or mmol/L.
- Click Calculate LDL.
- Review the calculated LDL-C and category.
- Interpret the result together with the complete lipid profile and clinical context.
Limitations of Calculated LDL
- The Friedewald equation provides an estimated LDL-C rather than a direct measurement.
- It is not recommended when triglycerides are ≥400 mg/dL.
- Accuracy may decrease with elevated triglycerides.
- Accuracy may be limited at very low LDL-C concentrations.
- Alternative LDL-C equations may be preferable in selected situations.
- Direct LDL-C testing may be appropriate when calculated LDL-C is considered unreliable.
Frequently Asked Questions
What is LDL cholesterol?
LDL cholesterol is cholesterol carried within low-density lipoprotein particles and is an important marker used in cardiovascular risk assessment.
What formula does this calculator use?
This calculator uses the traditional Friedewald equation: LDL-C = Total Cholesterol − HDL-C − Triglycerides/5 when values are expressed in mg/dL.
Can LDL be calculated in mmol/L?
Yes. This calculator supports both mg/dL and mmol/L and automatically uses the corresponding Friedewald equation.
Can Friedewald LDL be calculated when triglycerides are 400 mg/dL?
No. The traditional Friedewald equation is not recommended when triglycerides are 400 mg/dL or higher.
Is calculated LDL the same as direct LDL?
No. Calculated LDL-C is mathematically estimated from other lipid measurements, while direct LDL-C is obtained using a laboratory assay.
What is very high LDL cholesterol?
An LDL-C concentration of 190 mg/dL or higher is commonly classified as very high and warrants appropriate clinical evaluation.
Can Friedewald LDL be inaccurate?
Yes. The accuracy of calculated LDL-C can decrease with elevated triglycerides and at very low LDL-C concentrations.
What is non-HDL cholesterol?
Non-HDL cholesterol is calculated by subtracting HDL cholesterol from total cholesterol and represents cholesterol carried by multiple atherogenic lipoproteins.
Disclaimer
This calculator is provided for educational and laboratory reference purposes only. Calculated LDL-C is an estimate and should not be used as the sole basis for diagnosis, treatment, or medication decisions.
Clinical interpretation should be performed by a qualified healthcare professional using the complete lipid profile, cardiovascular risk assessment, applicable guidelines, and clinical context.
References
Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge.
Guidelines for the Management of Dyslipidemia
