LDL Calculator

Estimate LDL ("bad") cholesterol from a standard lipid panel using the Friedewald equation, along with non-HDL cholesterol and the TC/HDL ratio.

Quick Facts

Formula
LDL = TC - HDL - TG/5 (mg/dL)
The Friedewald equation, the most widely used LDL estimate since 1972.
Reliability limit
Triglycerides under 400 mg/dL
Above that, the formula's assumptions break down and a direct LDL test is preferred.
Sample timing
Fasting 9-12 hours recommended
Non-fasting triglycerides run higher and can skew the calculated LDL downward.

Your Results

Calculated
LDL cholesterol
-
Friedewald estimate
Non-HDL cholesterol
-
Total cholesterol minus HDL
TC / HDL ratio
-
Cardiovascular risk indicator
LDL category
-
Common adult reference band

Ready

Enter a fasting lipid panel (total cholesterol, HDL, triglycerides), then calculate.

About the LDL calculator

This calculator estimates LDL ("bad") cholesterol from a standard fasting lipid panel using the Friedewald equation, the method most labs and clinicians have used since it was published in 1972: LDL = Total Cholesterol - HDL - (Triglycerides / 5), with every value in mg/dL. The formula works because most triglycerides in the blood are carried by VLDL particles, and VLDL cholesterol is approximated as triglycerides divided by 5 in a fasting sample. Subtracting HDL and that VLDL estimate from total cholesterol leaves LDL.

How to get accurate results

  • Use the exact numbers from a lipid panel report - total cholesterol, HDL cholesterol, and triglycerides, all in mg/dL.
  • Use a fasting sample (9-12 hours) when possible: the TG/5 approximation for VLDL assumes fasting triglycerides.
  • Do not use this formula when triglycerides exceed 400 mg/dL - the estimate becomes unreliable and can even go negative. A direct (measured) LDL test is the right choice instead.

Putting the result in context

Alongside the calculated LDL, the tool reports non-HDL cholesterol (total cholesterol minus HDL, which captures all the atherogenic particles including LDL and VLDL) and the TC/HDL ratio, both of which stay useful even when triglycerides are high or the sample was not fasting. Compare your LDL to the common adult reference bands, but remember these are population-based cut points, not a personal target - your ideal LDL depends on other cardiovascular risk factors your clinician will weigh.

When to consult a professional

This calculator performs the standard Friedewald arithmetic for education and tracking; it does not diagnose, treat, or replace a directly measured LDL test. For any result that concerns you, for triglycerides above 400 mg/dL, or for decisions about diet, lifestyle, or medication, consult a licensed healthcare provider.

Frequently Asked Questions

What formula does this LDL calculator use?
It uses the Friedewald equation, the standard method labs have used since 1972: LDL = Total Cholesterol - HDL - (Triglycerides / 5), with all values in mg/dL. The calculator also reports non-HDL cholesterol (Total Cholesterol minus HDL) and the TC/HDL ratio, two figures often reviewed alongside LDL.
Why is the Friedewald equation inaccurate at high triglycerides?
The formula assumes VLDL cholesterol equals triglycerides divided by 5, a ratio that only holds for a fasting sample with triglycerides under about 400 mg/dL. Above that level the assumption breaks down, the calculated LDL becomes unreliable and can even turn negative, and a direct (measured) LDL test is recommended instead.
What is considered a healthy LDL level?
Commonly used adult reference bands are: under 100 mg/dL optimal, 100 to 129 near or above optimal, 130 to 159 borderline high, 160 to 189 high, and 190 mg/dL or above very high. Personal targets vary with other cardiovascular risk factors, so review any result with a healthcare provider rather than treating these bands as a diagnosis.

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