Cholesterol Ratio Calculator (with Friedewald LDL)
Enter your lipid panel to see your cholesterol ratios and estimated LDL.
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Cholesterol Ratio Calculator (with Friedewald LDL) by TheCalcTools
How the Cholesterol Ratio Calculator (with Friedewald LDL) works
The Friedewald equation estimates LDL as total cholesterol − HDL − triglycerides ÷ 5 (in mg/dL; ÷ 2.2 in mmol/L). It is not valid when triglycerides exceed 400 mg/dL (4.5 mmol/L), when the estimate is left blank.
A total-to-HDL ratio below about 5 (ideally below 3.5) is often used as a rough marker of lower risk. Your clinician assesses risk with full risk calculators.
The formula
Worked example
Using the default values shown in the calculator:
| Units | mg/dL |
|---|---|
| Total cholesterol | 200 |
| HDL cholesterol | 50 |
| Triglycerides | 150 |
- LDL = 200 − 50 − 150 ÷ 5 = 120 mg/dL.
- Total ÷ HDL = 4.0; non-HDL = 150 mg/dL.
Result:
| Total ÷ HDL ratio | 4.00 |
|---|---|
| LDL (Friedewald estimate) | 120.0 |
| Non-HDL cholesterol | 150.0 |
| LDL ÷ HDL ratio | 2.40 |
| Triglyceride ÷ HDL ratio | 3.00 |
Frequently asked questions
Is a direct LDL test better?
When triglycerides are high or LDL is very low, direct measurement or newer equations such as Martin-Hopkins or Sampson are more accurate.
Sources and further reading
- Friedewald WT et al. (1972) Estimation of LDL cholesterol concentration. Clin Chem 18:499
- Wikipedia: Cholesterol
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This calculator gives general estimates for information and education. It is not medical advice and does not diagnose anything. Talk to a qualified health professional about your own situation. See our disclaimer.