LDL Cholesterol Calculator
Estimate your LDL ("bad") cholesterol from a standard lipid panel. Enter total cholesterol, HDL and triglycerides in mg/dL or mmol/L, pick the Friedewald or the more accurate Martin-Hopkins equation, and see your VLDL, non-HDL and the clinical band you fall into. You can also reverse-solve the total cholesterol needed to hit a target LDL.
Formula
Worked example
With total cholesterol 200, HDL 50 and triglycerides 150 mg/dL: non-HDL = 150. Friedewald uses VLDL = 150 ÷ 5 = 30, so LDL = 200 − 50 − 30 = 120 mg/dL. Martin-Hopkins picks a factor near 5.7 here, giving VLDL ≈ 26 and LDL ≈ 124 mg/dL, both near optimal.
How LDL is estimated from your lipid panel
Most lab reports do not measure LDL cholesterol directly; they calculate it from the other values on your panel. The classic Friedewald equation subtracts your HDL ("good") cholesterol and an estimate of VLDL cholesterol from your total cholesterol, approximating VLDL as triglycerides divided by five. The remainder is your LDL, the fraction most strongly linked to clogged arteries. Enter your numbers in mg/dL or mmol/L and the calculator handles the conversion (cholesterol uses a factor of about 38.67, triglycerides about 88.57).
Friedewald vs Martin-Hopkins
The Friedewald fixed factor of five is only an average. The newer Martin-Hopkins method replaces it with an adjustable factor chosen from a published table based on your triglyceride and non-HDL levels, which better matches how VLDL actually tracks triglycerides. In a study of more than five million patients, Martin-Hopkins classified LDL into the correct category about 90% of the time versus 83% for Friedewald, and it stays usable when triglycerides are high. Friedewald becomes unreliable and is not used at or above 400 mg/dL (about 4.5 mmol/L); this calculator returns no Friedewald result there and suggests switching to Martin-Hopkins or a direct measurement.
What your LDL number means for your heart
LDL particles deposit cholesterol in artery walls, where it builds into plaque that narrows vessels and can trigger heart attacks and strokes. Lower LDL is generally better: US guidelines treat below 100 mg/dL as optimal and 190 mg/dL or above as very high, while European guidelines set risk-based goals (below about 116 mg/dL for low risk down to below 55 mg/dL for very high risk). Non-HDL cholesterol and the total-to-HDL ratio, both shown above, are useful companion measures, especially when triglycerides are elevated.
Reverse mode: total cholesterol for a target LDL
Switch the mode to "Total cholesterol for a target LDL" to work the equation backwards. Enter the LDL you want to reach along with your current HDL and triglycerides, and the calculator returns the total cholesterol that would produce it (Total = LDL + HDL + VLDL). This is a planning aid rather than a prescription: in real life lowering LDL usually shifts HDL and triglycerides too, so treat the figure as a rough goalpost and set actual targets with your clinician.
LDL categories and risk-based targets
| LDL (mg/dL) | Category | Risk group | LDL goal (mg/dL) |
|---|---|---|---|
| Below 100 | Optimal | Low risk | Below 116 |
| 100-129 | Near optimal | Moderate risk | Below 100 |
| 130-159 | Borderline high | High risk | Below 70 |
| 160-189 | High | Very high risk | Below 55 |
| 190 and above | Very high | Familial / recurrent | Below 40 (some) |
Left: the NCEP ATP III LDL bands (mg/dL). Right: LDL goals by cardiovascular risk from the ESC/EAS guidelines. Lower LDL means lower cardiovascular risk.
Frequently asked questions
Which equation should I use, Friedewald or Martin-Hopkins?
Martin-Hopkins is more accurate, especially when LDL is low or triglycerides are raised, because it uses an adjustable VLDL factor instead of Friedewald's fixed division by five. Many labs and guidelines now prefer it. Friedewald is still widely reported and fine for routine screening when triglycerides are below 400 mg/dL; this calculator offers both.
Can I enter my results in mmol/L?
Yes. Switch the units selector to mmol/L and enter all values that way; the calculator converts internally (cholesterol at roughly 38.67 mg/dL per mmol/L and triglycerides at about 88.57) and shows the LDL, VLDL and non-HDL back in mmol/L.
Do I need to fast before the blood test?
Fasting for 9-12 hours has traditionally been recommended because eating raises triglycerides, which affects the VLDL estimate. Many guidelines now accept non-fasting panels for screening, but follow the instructions your clinician or lab gives you.
What LDL level should I aim for?
Below 100 mg/dL is considered optimal for most adults, with low-risk goals around 116 mg/dL. People at high or very high cardiovascular risk are often advised to aim much lower, below 70 or even 55 mg/dL. There is no single target for everyone; your doctor sets a goal based on your overall risk profile.