There is no single normal value, because the level that matters depends on your overall cardiovascular risk. For reference, the Adult Treatment Panel III classification calls below 100 mg/dL (2.59 mmol/L) optimal, 100–129 mg/dL near optimal, 130–159 mg/dL borderline high, 160–189 mg/dL high, and 190 mg/dL (4.9 mmol/L) or above very high. Treatment goals sit far below the top of those bands for people at higher risk: below 70 mg/dL (1.8 mmol/L) for high risk and below 55 mg/dL (1.4 mmol/L) for very high risk in the 2019 ESC/EAS guidelines.

The full LDL cholesterol chart →

The standard calculation is the Friedewald equation, published in 1972: LDL-C = total cholesterol − HDL cholesterol − triglycerides ÷ 5 in mg/dL, or triglycerides ÷ 2.2 in mmol/L. The division estimates the cholesterol carried in VLDL particles, which are not measured directly. LDL itself is never measured, which is why the result is called a calculated or estimated LDL rather than a measured one.

How the equation works →

In mg/dL the divisor of 5 comes from the composition of a VLDL particle. In the fasting state VLDL carries roughly one fifth as much cholesterol as triglyceride by mass, so dividing the triglyceride concentration by 5 estimates the cholesterol that VLDL is carrying, and subtracting it leaves the cholesterol in LDL. The SI form uses 2.2 rather than the mathematically equivalent 2.18, which is why a panel calculated in mmol/L can differ by about 0.01 mmol/L from the same panel calculated in mg/dL.

It fails in four situations. Triglycerides of 400 mg/dL (4.5 mmol/L) or more: the assumption behind the divisor of 5 breaks down and the equation underestimates LDL cholesterol, which is why the original paper and every guideline since set that limit. Very low triglycerides, below about 50 mg/dL (0.6 mmol/L): the VLDL estimate becomes unreliable. Non-fasting samples: triglycerides rise after a meal, so the VLDL estimate is too large and LDL comes out too low. And conditions with abnormal lipoproteins, such as chylomicronaemia or type III dyslipidaemia, where a fixed divisor does not describe the particles present.

Yes. The divisor of 5 assumes fasting triglyceride levels, and a non-fasting sample can raise triglycerides enough to push the calculated LDL cholesterol down by a clinically meaningful amount. Most laboratories ask for 9 to 12 hours of fasting before a lipid panel, although some screening programmes now accept non-fasting samples and interpret triglycerides and non-HDL cholesterol rather than a calculated LDL.

Three common reasons. Rounding: reports round the inputs before calculating, or round the result, so a value can move by a milligram or two. A different equation: some laboratories now use the Martin–Hopkins adjustable factor or the Sampson equation instead of Friedewald, and the three disagree most at high triglyceride or low LDL levels. A direct measurement: some assays measure LDL cholesterol physically rather than estimating it, which sidesteps the equation and is the right approach when triglycerides are above 400 mg/dL.

For the great majority of people, yes. Guidelines accept the calculated value for screening and for monitoring statin treatment as long as triglycerides are below 400 mg/dL. Direct measurement is preferred when triglycerides are very high, when the calculated result looks inconsistent with the rest of the panel, and in people with conditions that distort lipoprotein composition. Where the two disagree, a clinician will usually trust the direct measurement.

The SI form divides triglycerides by 2.2. That is not an exact unit conversion of the mg/dL form — dividing by 5 in mg/dL is equivalent to dividing by about 2.18 in mmol/L — but 2.2 is the value the SI literature and laboratory practice specify, so this calculator uses 2.2 when you enter mmol/L and 5 when you enter mg/dL, exactly as published for each unit.

Unit conversion factors →

The Friedewald equation is not valid there, so do not rely on the calculated LDL cholesterol. Non-HDL cholesterol — total cholesterol minus HDL cholesterol — stays valid at any triglyceride level and is the guideline-recommended alternative. Ask your clinician or laboratory for a direct LDL cholesterol measurement, or for a result calculated with the Martin–Hopkins or Sampson method, both of which remain accurate at higher triglycerides. Very high triglycerides are also worth treating in their own right.

Non-HDL cholesterol is total cholesterol minus HDL cholesterol. It counts every cholesterol-carrying particle that is not HDL — including VLDL, remnant particles and LDL — so it captures the atherogenic particles a calculated LDL can miss. It needs no fasting, needs no equation, and stays meaningful when triglycerides are high. Most lipid guidelines recommend it as a secondary target, usually around 30 mg/dL above the LDL cholesterol target.

Non-HDL cholesterol calculator →

No. The calculation runs entirely inside your browser and the page sends no data anywhere. There is no account, no analytics script and no advertising on this site, and nothing you type is stored on a server. The only place your numbers persist is the address bar, because the page writes them into the URL so that a link can reproduce the same calculation; closing the tab clears it.

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It depends on your overall cardiovascular risk, not on the number alone. The 2019 ESC/EAS guidelines suggest below 116 mg/dL (3.0 mmol/L) for low risk, below 100 mg/dL (2.6 mmol/L) for moderate risk, below 70 mg/dL (1.8 mmol/L) plus a 50% reduction for high risk, and below 55 mg/dL (1.4 mmol/L) plus a 50% reduction for very high risk. The 2018 AHA/ACC guideline instead assigns statin intensity by risk group rather than naming a numeric target. A target is a clinical decision made with your own history in front of you.