Cholesterol Math: Friedewald LDL, Non-HDL, and Ratios
October 29, 2026
A standard lipid panel reports total cholesterol, HDL (often called 'good'), triglycerides, and usually LDL. Many labs calculate LDL instead of measuring it directly, using the Friedewald equation: LDL = total cholesterol − HDL − triglycerides ÷ 5 (all in mg/dL). The triglycerides ÷ 5 term estimates the cholesterol carried by VLDL particles.
For total cholesterol 200, HDL 50, and triglycerides 150: LDL = 200 − 50 − 150 ÷ 5 = 200 − 50 − 30 = 120 mg/dL. Non-HDL cholesterol = total − HDL = 150 mg/dL. The total-to-HDL ratio is 200 ÷ 50 = 4.0.
Skip the math and get your answer instantly:
Open the BMI Calculator →Two Worked Panels
Panel A is the example above. Panel B: total 240, HDL 40, triglycerides 250. LDL = 240 − 40 − 250 ÷ 5 = 240 − 40 − 50 = 150 mg/dL. Non-HDL = 200. Total/HDL = 6.0, and triglyceride/HDL = 6.25. Panel B is notably less favorable on every measure. Non-HDL cholesterol captures all the atherogenic particles (LDL, VLDL, and others) and does not need fasting, so some guidelines use it as a secondary target.
Typical reference points for adults in the US: total below 200, LDL below 100 for optimal (targets are lower for people at high risk), HDL above 40 for men and 50 for women, triglycerides below 150, and non-HDL below 130. Your clinician sets targets based on your overall risk.
| Measure | Panel A | Panel B |
|---|---|---|
| Total cholesterol | 200 | 240 |
| HDL | 50 | 40 |
| Triglycerides | 150 | 250 |
| LDL (Friedewald) | 120 | 150 |
| Non-HDL | 150 | 200 |
| Total / HDL ratio | 4.0 | 6.0 |
| Triglyceride / HDL ratio | 3.0 | 6.25 |
When the Formula Fails
The Friedewald equation becomes inaccurate when triglycerides are above about 400 mg/dL, and it underestimates LDL when triglycerides are high or LDL is very low. Newer equations (such as the Martin-Hopkins and Sampson methods) improve accuracy, and direct LDL measurement is available. If your calculated LDL looks surprising, ask whether the lab used an alternate method.
Lifestyle Levers
Diet and exercise move the numbers: replacing saturated fat with unsaturated fat, increasing soluble fiber, losing excess weight, being physically active, limiting alcohol and refined carbohydrates (which lower triglycerides), and quitting smoking (which raises HDL). Medication may be recommended based on overall cardiovascular risk, not on a single number. Ask your clinician about your 10-year risk estimate.
Using the Ratios
The total/HDL ratio is a simple risk indicator: below 5 is commonly recommended, and below 3.5 is considered better. Ratios can be misleading on their own, since a high HDL and a high LDL can give a deceptively good ratio. Track the individual values over time and discuss the trend with a healthcare professional. This article is educational, not medical advice.
Frequently Asked Questions
What is the Friedewald equation?
LDL = total cholesterol − HDL − triglycerides ÷ 5.
What is non-HDL cholesterol?
Total cholesterol minus HDL.
When is the Friedewald formula unreliable?
When triglycerides exceed about 400 mg/dL.
Do I need to fast for a lipid panel?
Often not, but your clinician or lab will advise.
Is a lower total/HDL ratio better?
Generally yes; below 5 is a common target.