Friedewald LDL CalculatorFree online fitness & health calculator — instant results, no sign-up
Estimate LDL cholesterol from total cholesterol, HDL and triglycerides.
For general information only. This is not medical advice, diagnosis, dosing guidance or a treatment recommendation. Talk to a doctor or other qualified health professional about your health, pregnancy, or diet.
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About the Friedewald LDL Calculator
The Friedewald LDL Calculator estimates LDL cholesterol from total cholesterol, HDL cholesterol, and triglycerides entered in mg/dL. It uses the Friedewald equation, which approximates very-low-density lipoprotein (VLDL) cholesterol as triglycerides divided by 5. This tool provides an educational estimate for adults, not a diagnosis or treatment recommendation.
- Total cholesterol (mg/dL)
- Total cholesterol is the cholesterol carried by all lipoproteins in your blood, measured in mg/dL; the default is 190.
- HDL cholesterol (mg/dL)
- HDL cholesterol is the cholesterol carried by high-density lipoproteins, measured in mg/dL; the default is 55.
- Triglycerides (mg/dL)
- Triglycerides are a type of blood fat used to estimate VLDL cholesterol in this equation, measured in mg/dL; the default is 120.
Formula and method
LDL_est = TC − HDL − (TG / 5). With the default inputs: LDL_est = 190 − 55 − (120 / 5) = 190 − 55 − 24 = 111 mg/dL.
- LDL_estEstimated low-density lipoprotein cholesterol, in mg/dL.
- TCTotal cholesterol, in mg/dL.
- HDLHigh-density lipoprotein cholesterol, in mg/dL.
- TGTriglycerides, in mg/dL; TG / 5 approximates VLDL cholesterol in mg/dL.
Divide triglycerides by 5 to estimate VLDL cholesterol, then subtract both HDL cholesterol and estimated VLDL cholesterol from total cholesterol. For the default inputs, the estimated VLDL cholesterol is 24 mg/dL and the estimated LDL cholesterol is 111 mg/dL. Check the triglyceride value before interpreting the result: the Friedewald estimate is not valid at triglycerides ≥400 mg/dL.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Total cholesterol190 mg/dL
- HDL cholesterol55 mg/dL
- Triglycerides120 mg/dL
Results
- Estimated LDL cholesterol111 mg/dL
- NoteNot valid at triglycerides ≥400 mg/dL; less accurate with low LDL or elevated triglycerides.
- NoteEducational estimate for adults; not a diagnosis or treatment recommendation.
How to use the Friedewald LDL Calculator
- 1Find total cholesterol, HDL cholesterol, and triglycerides from the same lipid panel, and confirm that all values are in mg/dL.
- 2Enter total cholesterol; use 190 mg/dL to reproduce the default example.
- 3Enter HDL cholesterol as 55 mg/dL and triglycerides as 120 mg/dL for the default example.
- 4Run the calculation and read the estimated LDL cholesterol, which is 111 mg/dL for these inputs.
- 5Read both note rows before using the estimate, and discuss its clinical meaning with a healthcare professional.
Reading your result
The “Estimated LDL cholesterol” row reports calculated rather than directly measured LDL cholesterol; the default result is 111 mg/dL. The first “Note” row states: “Not valid at triglycerides ≥400 mg/dL; less accurate with low LDL or elevated triglycerides.” It describes when the equation is unreliable, even if an arithmetic result can be produced. The second “Note” row states: “Educational estimate for adults; not a diagnosis or treatment recommendation.” Whether an LDL value meets an appropriate goal depends on cardiovascular risk, medical history, and clinical guidance.
Limitations
The equation assumes a fixed relationship between triglycerides and VLDL cholesterol, which does not hold equally well for everyone. It is not valid at triglycerides ≥400 mg/dL and becomes less accurate with low LDL cholesterol or elevated triglycerides below that cutoff. It was developed using fasting samples; recent food intake can affect triglycerides and the reliability of the estimate. Certain lipid disorders can also invalidate its assumptions. Use values from the same blood draw, in mg/dL only. A negative estimate is not a meaningful LDL concentration and should prompt review of the inputs and laboratory results. This adult educational tool does not establish a diagnosis, assess overall cardiovascular risk, or determine treatment.
Common questions
Why does the Friedewald equation divide triglycerides by 5?+
When values are in mg/dL, triglycerides divided by 5 approximates the cholesterol carried by VLDL particles. Subtracting that estimate and HDL cholesterol from total cholesterol leaves an estimate of LDL cholesterol.
How do the default inputs produce an LDL estimate of 111 mg/dL?+
Using total cholesterol of 190 mg/dL, HDL cholesterol of 55 mg/dL, and triglycerides of 120 mg/dL, the calculation is 190 − 55 − (120 / 5) = 111 mg/dL.
Can I use the result if triglycerides are 400 mg/dL or higher?+
No. The Friedewald equation is not valid at triglycerides ≥400 mg/dL. A clinician or laboratory may use another estimation method or a direct LDL measurement, depending on the circumstances.
Why might this estimate differ from the LDL value on my laboratory report?+
Your laboratory may use a different LDL estimation equation or directly measure LDL cholesterol. Differences are particularly important when LDL is low or triglycerides are elevated, where the Friedewald equation is less accurate.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
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Results are estimates for informational purposes and are not financial, medical or legal advice.