LDL Cholesterol (Friedewald)
Medical context
Estimate LDL-C from total cholesterol, HDL, and triglycerides using Friedewald.
Cardiology and medicine teams use this with ECG, biomarkers, and guideline-directed therapy context.
This page explains the LDL formula, how to interpret the output, known limitations, and peer-reviewed references so you can verify results against primary sources and local protocols.
It is grouped under Cardiology because stroke prevention, acs risk, and cardiac indices.
How to use this calculator
- Enter the values requested by the LDL calculator using the units shown beside each field.
- Review the calculated result and read the interpretation section before acting on the output.
- Check limitations and references if the result will change management, dosing, or disposition.
- Use the related calculators section when you need supporting values (for example electrolytes, weight, or complementary risk scores).
Calculator
Result
120 mg/dL
Friedewald LDL-C
Educational use only. Confirm results with clinical judgment, primary sources, and local protocols. Not a substitute for professional medical advice. Full disclaimer.
Formula
LDL = TC − HDL − TG/5 (mg/dL). Invalid if TG ≥400.
Interpretation
Use for routine lipid panels when triglycerides are not markedly elevated.
Limitations
Inaccurate with TG ≥400, non-fasting extremes, and some dyslipidemias — use direct LDL.
Frequently asked questions
- Why invalid above TG 400?
- The VLDL ≈ TG/5 assumption breaks down at high triglyceride levels.
- Is the LDL result enough to make a treatment decision?
- No. Calculators support medical decision-making but do not replace examination, shared decision-making, institutional protocols, or consultant input when stakes are high.
- Does Calcmedical store the values I type in?
- Inputs are processed in your browser for this session. We do not ask for patient names or medical record numbers. See our privacy policy for hosting and analytics details.
References
- Friedewald WT et al. Clin Chem.