LDL Cholesterol Calculator
Estimate the LDL from a standard lipid panel.
LDL Cholesterol Calculator
Friedewald LDL = total cholesterol - HDL - triglycerides / 5, all in mg/dL.
Calculated instantly
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What This Calculator Does
The LDL Cholesterol Calculator estimates LDL cholesterol from total cholesterol, HDL cholesterol, and triglycerides using the Friedewald equation. It also reports non-HDL cholesterol and two common ratios, with the limits of the estimate stated plainly.
How It Works
The Friedewald equation treats VLDL cholesterol as triglycerides divided by 5, then subtracts VLDL and HDL from total cholesterol. The result is an LDL estimate in mg/dL. Non-HDL is total minus HDL. The total-to-HDL ratio divides total cholesterol by HDL, and the triglyceride-to-HDL ratio divides triglycerides by HDL. All inputs must be in mg/dL.
Example
Total cholesterol 200, HDL 50, and triglycerides 150 give an estimated LDL of 200 - 50 - 30 = 120 mg/dL. Non-HDL is 150 mg/dL, the total-to-HDL ratio is 4.0, and the triglyceride-to-HDL ratio is 3.0.
Formula
total cholesterol - HDL - triglycerides / 5total cholesterol - HDLtotal cholesterol / HDLtriglycerides / HDLReading the Results
Estimated LDL cholesterol
A calculated value, not a direct measurement. It is the number most lipid panels report when triglycerides are in the valid range.
Non-HDL cholesterol
Total cholesterol minus HDL, representing cholesterol carried by LDL, VLDL, and other atherogenic particles. It remains meaningful when triglycerides are high.
Triglyceride to HDL ratio
A simple marker associated with insulin resistance and metabolic risk. It is not a diagnosis and should be interpreted with the rest of the panel.
Sources and References
National Cholesterol Education Program - ATP III Guidelines
Friedewald equation and lipid targets
The source of the widely used LDL estimate and the lipid categories it was built around.
American Heart Association - Cholesterol and lipid testing
Lipid panel interpretation
Patient-facing guidance on cholesterol numbers and the need for clinician risk assessment.
References identify the method or data behind this calculator. Where a standard or tariff changes, the current edition applies, and the assumptions stated above take precedence over a remembered figure.
Frequently Asked Questions
What is the Friedewald equation?
LDL = total cholesterol - HDL - triglycerides / 5, with all values in mg/dL. It estimates VLDL cholesterol from triglycerides and subtracts it. The equation is inexpensive and widely used, but it becomes unreliable at high triglycerides and very low LDL.
When is the LDL estimate unreliable?
At triglycerides of 400 mg/dL or more, the VLDL estimate is poor and many laboratories will not report a Friedewald LDL. Very low LDL values, certain genetic lipid disorders, and non-fasting samples can also distort it. A direct LDL assay is more reliable in those cases.
What is non-HDL cholesterol and why does it matter?
It is total cholesterol minus HDL, so it includes LDL, VLDL, and remnant cholesterol. It does not depend on the triglyceride assumption and is a useful secondary target, especially when triglycerides are elevated. Many guidelines treat it as a co-primary target.
Do I need to fast for a lipid panel?
Not always. Many guidelines allow non-fasting lipid testing for most people, but triglycerides rise after a meal and the Friedewald estimate is sensitive to them. Follow the instructions from the laboratory and clinician ordering the test.
Can this calculator tell me my heart disease risk?
No. It only does the lipid arithmetic. A risk estimate needs age, sex, blood pressure, diabetes status, smoking, cholesterol values, and sometimes additional markers. Use a validated risk tool with a clinician rather than a single number.