Lipid Panel Calculator: LDL, non-HDL and Atherogenic Indices

Calculated LDL by two methods, non-HDL, remnant cholesterol and five atherogenic indices from a standard lipid panel — with ESC/EAS target values.

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Result

LDL cholesterol (LDL-C): 3.49 mmol/L
Interpretation: LDL 3.0–4.1 mmol/L: above target for most adults
LDL by Friedewald: 3.42 mmol/L
LDL by Sampson: 3.49 mmol/L
Non-HDL cholesterol: 4.10 mmol/L
Remnant cholesterol: 0.61 mmol/L
Atherogenic index of plasma (AIP): 0.06 · low risk index
Atherogenic coefficient (Klimov): 3.15 · moderate risk index
Castelli indices I / II: 4.15 / 2.68 ratio
TG/HDL ratio: 1.15 ratio

Calculated per Friedewald 1972, Sampson 2020 and Dobiášová 2001; LDL categories per ESC/EAS 2019. Reference ranges are population benchmarks from the cited sources. Laboratories use their own ranges, and interpretation depends on clinical context: discuss the result with your physician.

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How it is calculated

From total cholesterol, HDL and triglycerides the calculator derives LDL with the classic Friedewald formula (1972) and with the Sampson equation (NIH, 2020), which stays accurate at triglycerides up to 9 mmol/L and at low LDL. Non-HDL is all atherogenic cholesterol (LDL + VLDL + remnant particles), and remnant cholesterol is non-HDL minus LDL. The Castelli indices (TC/HDL and LDL/HDL), Klimov’s atherogenic coefficient and the atherogenic index of plasma AIP = log10(TG/HDL) reflect the balance of "bad" and "protective" fractions and predict risk better than single markers.

Formula

LDL (Friedewald, mmol/L) = TC − HDL − TG / 2.2 [when TG ≤ 4.5 mmol/L] LDL (Sampson, mg/dL) = TC/0.948 − HDL/0.971 − (TG/8.56 + TG×non-HDL/2140 − TG²/16100) − 9.44 non-HDL = TC − HDL; Remnant-C = non-HDL − LDL AC (Klimov) = (TC − HDL) / HDL; Castelli I = TC/HDL; Castelli II = LDL/HDL AIP = log10(TG / HDL), mmol/L

Limits of the method

Calculated LDL is an estimate, not a measurement: at TG > 4.5 mmol/L Friedewald does not apply, and at TG > 9 mmol/L or chylomicronemia even Sampson is inaccurate. The indices do not replace overall risk assessment by SCORE2, apolipoprotein B and lipoprotein(a). LDL targets depend on the risk category (1.4 to 3.0 mmol/L per ESC/EAS 2019) and are set by a physician. Fasting or non-fasting per your lab’s instructions.

Sources of the method

This calculation is for reference only and is not medical advice, a diagnosis or a prescription. If you have a medical condition, are pregnant, take medication or have any doubts, discuss the result with a physician or a qualified nutrition professional.

How to read a lipid panel step by step

Enter the three basic markers

Total cholesterol, HDL and triglycerides are on every lipid panel. Choose the units on your report: mmol/L (Europe, CIS) or mg/dL (USA, some Latin American labs).

Add measured LDL if available

Direct LDL measurement is more accurate than calculation. If absent, the calculator uses the Sampson equation and shows Friedewald in parallel for comparison with your lab report.

Look at ratios, not a single number

Normal total cholesterol with low HDL and high triglycerides is an atherogenic profile. AIP and the atherogenic coefficient reveal it when "TC is normal".

Lipid panel worked examples

FavorableLDL 2.68

TC 4.6 · HDL 1.5 · TG 1.0 mmol/L

Friedewald 2.65, Sampson 2.68 — the methods agree. Non-HDL 3.1, AIP −0.18, AC 2.07, TC/HDL 3.07. All indices in the low-risk zone.

Profile of a person without risk factors; repeat every 4–5 years.

AtherogenicLDL 3.88

TC 5.9 · HDL 1.1 · TG 2.2 mmol/L

Total cholesterol "slightly above normal", but AIP 0.30 and AC 4.36 mean high risk. Remnant cholesterol 0.92 mmol/L. Friedewald underestimates LDL (3.80) versus Sampson (3.88).

Typical insulin-resistance profile: low HDL + high TG.

High riskLDL 4.20

TC 6.8 · HDL 0.9 · TG 3.9 mmol/L

All indices in the red zone: AIP 0.64, AC 6.56, TC/HDL 7.56, remnant-C 1.7 mmol/L. At TG 3.9 Friedewald (4.13) is already at the edge of validity.

ApoB, Lp(a), SCORE2 risk assessment and an in-person cardiology visit are indicated.

Why non-HDL and remnant cholesterol matter more than they seem

LDL is not the only atherogenic lipoprotein. VLDL and their triglyceride-rich remnants enter the vessel wall just like LDL, and in the Copenhagen cohorts each 1 mmol/L of remnant cholesterol raised ischemic heart disease risk 2.8-fold. That is why ESC/EAS 2019 recommend non-HDL as a secondary treatment target and, at triglycerides above 2 mmol/L, as a marker no less important than LDL.

Friedewald vs Sampson: when the old formula fails

Friedewald assumes a constant cholesterol-to-triglyceride ratio in VLDL (1:2.2 in mmol/L). At triglycerides above 2 mmol/L and especially at LDL below 1.8 mmol/L it underestimates LDL by 10–30%, so a patient on statins may look "at target" without being there. The Sampson equation, derived by the NIH from 8,656 ultracentrifuged samples, removes that error and is valid up to TG 9 mmol/L. We show both: Friedewald to cross-check the lab report, Sampson for clinical conclusions.

LDL and non-HDL targets by risk category (ESC/EAS 2019)

Risk category	LDL target	Non-HDL target
Low	< 3.0 mmol/L (116 mg/dL)	< 3.8 mmol/L
Moderate	< 2.6 mmol/L (100 mg/dL)	< 3.4 mmol/L
High	< 1.8 mmol/L (70 mg/dL) and ≥ 50% reduction	< 2.6 mmol/L
Very high	< 1.4 mmol/L (55 mg/dL) and ≥ 50% reduction	< 2.2 mmol/L
Recurrent event within 2 years	< 1.0 mmol/L (40 mg/dL)	< 1.8 mmol/L

The risk category is set by a physician from SCORE2/SCORE2-OP, diabetes, CKD, atherosclerosis and familial hypercholesterolemia. The calculator shows the LDL category, not the patient’s risk category.

Frequently asked questions

What atherogenic coefficient is normal?

Klimov’s atherogenic coefficient (TC − HDL)/HDL below 3 is normal, 3–4 moderately elevated, above 4 high. It is widely used in the CIS, whereas international guidelines more often rely on non-HDL and the TC/HDL ratio.

Why does the calculator’s LDL differ from my lab report?

Most labs calculate LDL by Friedewald; some measure it directly. The calculator shows Friedewald for cross-checking and Sampson as the more accurate estimate. A 0.1–0.3 mmol/L discrepancy at high triglycerides is expected.

What is AIP and why does it matter?

The atherogenic index of plasma AIP = log10(TG/HDL) reflects LDL particle size: the higher the AIP, the more small dense LDL, which penetrate the vessel wall more easily. AIP above 0.21 is associated with high risk even at normal LDL.

Do I need to fast for a lipid panel?

Per EAS/EFLM 2016 non-fasting samples are acceptable for screening: total cholesterol, HDL and LDL barely change after a meal, while triglycerides rise by about 0.3 mmol/L on average. Fasting is used when TG exceeds 4.5 mmol/L and for Friedewald LDL.

How can I lower LDL without medication?

Replacing saturated with unsaturated fat lowers LDL by 5–10%, soluble fiber (oats, legumes, psyllium) by another 5–7%, plant stanols by up to 10%, and losing 10 kg by about 0.2 mmol/L. Triglycerides respond most to cutting alcohol and added sugars. In familial hypercholesterolemia diet does not replace therapy.

What is remnant cholesterol?

It is the cholesterol in VLDL and intermediate-density lipoproteins: non-HDL minus LDL. At normal triglycerides it is 0.3–0.6 mmol/L; values above 0.8 mmol/L are linked to higher infarction risk independently of LDL.

The lipid profile is tightly linked to insulin resistance and visceral fat:

TyG Index Calculator (Triglycerides × Glucose) →HOMA-IR Calculator: Insulin Resistance Index →Omega-3 Intake & Index Calculator (EPA + DHA) →Waist Anthropometric Index Calculator (WHtR, WHR, VAI) →Dietary Fiber Intake Calculator (WHO & EFSA) →

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What next

Formula breakdowns, biomarker reference ranges and nutrition articles with cited sources are in the NutriFit knowledge base.

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