Enter Lipid Inputs
The form uses a responsive 3-column layout on large screens, 2-column layout on smaller screens, and 1-column layout on mobile.
Formula Used
1) ApoB Particle Count
ApoB particle count (nmol/L) = ApoB (mg/dL) × 19.53125
2) Estimated LDL Particle Number
Estimated LDL-P (nmol/L) = ApoB particle count × (LDL share ÷ 100)
3) Non-HDL Cholesterol
Non-HDL-C (mg/dL) = Total Cholesterol − HDL-C
4) LDL-C Fallback Estimate
LDL-C (mg/dL) = Total Cholesterol − HDL-C − (Triglycerides ÷ 5) − Lp(a)-C adjustment
5) LDL-C to ApoB Ratio
LDL-C/ApoB ratio = LDL-C ÷ ApoB
This page uses an estimation workflow. Direct LDL particle testing can produce different values because particle composition varies between samples.
How to Use This Calculator
- Enter ApoB and choose its unit.
- Set the estimated LDL share percentage. A common starting assumption is 90%.
- Enter your target LDL-P for comparison.
- Optionally add total cholesterol, HDL-C, triglycerides, direct LDL-C, and any Lp(a)-C adjustment.
- Click the calculate button.
- Review the result banner, summary cards, and Plotly graph shown below the header and above the form.
- Use the CSV or PDF buttons to export the calculation summary.
- Use the example table below to compare your entries with sample profiles.
Example Data Table
| Profile | ApoB (mg/dL) | Total-C | HDL-C | TG | LDL Share (%) | Estimated LDL-C | Estimated LDL-P (nmol/L) |
|---|---|---|---|---|---|---|---|
| Example A | 65 | 170 | 50 | 100 | 90 | 100 | 1142.58 |
| Example B | 80 | 190 | 48 | 140 | 90 | 114 | 1406.25 |
| Example C | 95 | 220 | 45 | 180 | 92 | 139 | 1707.03 |
| Example D | 110 | 245 | 42 | 220 | 92 | 159 | 1976.56 |
Example LDL-C values above use the routine-lipid fallback equation with no Lp(a)-C adjustment.
Frequently Asked Questions
1) What is LDL particle number?
LDL particle number estimates how many LDL particles circulate in blood. It focuses on particle count rather than only the cholesterol mass carried inside those particles.
2) Why does this calculator use ApoB?
ApoB is commonly used as a particle-count proxy in lipid analysis. This calculator turns ApoB into an estimated particle concentration, then applies a user-selected LDL share.
3) Is this the same as a direct LDL-P lab result?
No. This page provides an estimate. Direct laboratory methods can report different numbers because particle composition and measurement technique are not identical to this simplified model.
4) What does LDL share mean?
LDL share is the percentage of ApoB-containing particles you want to treat as LDL for the estimate. It lets you adjust the model instead of forcing one fixed assumption.
5) Can I enter direct LDL-C?
Yes. If you enter direct LDL-C, the calculator uses it for the LDL-C/ApoB ratio. Otherwise, it estimates LDL-C from routine lipid values when possible.
6) Why can LDL-C and LDL-P disagree?
Two people may carry similar cholesterol mass but in different numbers of particles. That is why particle-focused views and cholesterol-focused views can diverge.
7) Do triglycerides matter here?
Yes. Triglycerides affect the fallback LDL-C estimate and can influence how cholesterol is packaged across lipoproteins, which changes interpretation of ratios and patterns.
8) Is this calculator for diagnosis?
No. It is designed for educational and planning use. Diagnostic decisions should rely on laboratory methods, full clinical context, and professional interpretation.