Estimate LDL cholesterol with the Friedewald formula and find your non-HDL cholesterol and total/HDL ratio. Enter results in mg/dL. Free, private, and runs entirely in your browser.
The Friedewald formula estimates LDL by subtracting HDL and one fifth of the triglycerides from total cholesterol. Non-HDL cholesterol is total minus HDL, and the ratio is total divided by HDL.
What is a good total/HDL ratio? A ratio below 5 is generally considered desirable and below 3.5 optimal.
When is the Friedewald formula not valid? When triglycerides are 400 mg/dL or higher, or in some other special cases, where a direct LDL measurement is used.
Total cholesterol is 200, HDL is 50 and triglycerides are 150 mg/dL. LDL = 200 − 50 − 150 ÷ 5 = 120 mg/dL. Non-HDL = 150 mg/dL and the ratio is 200 ÷ 50 = 4.0, which falls in the desirable range.
Is non-HDL cholesterol useful? Yes. It covers all the atherogenic cholesterol and is less affected by fasting than LDL.
Can I convert mmol/L to mg/dL? Multiply cholesterol values in mmol/L by about 38.67 to get mg/dL.
The Friedewald formula was published in 1972 by William Friedewald, Robert Levy and Donald Fredrickson as a way to estimate LDL from a standard lipid panel without a costly ultracentrifuge test. It remains widely used, although newer equations were developed for cases with high triglycerides or very low LDL.
Use this calculator to understand a lipid panel before an appointment. This is general information, not medical advice. Talk to a doctor or other qualified professional about your own results.
What is a healthy LDL? It depends on your risk. Guidelines set different targets for people with and without heart disease, so ask your clinician.
How can I improve my cholesterol? Diet, activity, weight, not smoking and, when needed, medication all play a role. Your clinician can advise you.